Have POA for dad (92) with dementia. He can't recall passwords. How do I file his taxes when I can't get any info in a paperless world?

Can you at least access his email? If you can, you can change his passwords using the "forgot my password" feature. Those sites usually send a link to set up a new password to the email address on file.

You can sit next to dad and make phone calls. He gives his permission to speak to you and you can ask for paper forms. Start by forwarding his mail to you so you can catch the 1099s. Later you can deal with address changes later

I have an address book that I also use for my passwords. This is one reason I don't go paperless.

IF everything he does is paperless, they all must have an email address associated with his accounts. Start with email. If he can't recall the password, you'll have to work with whoever the provider is to get the password reset.

Once you have that (document it for yourself!), then each place you need information from, request a password reset (most login prompts have a "forgot password" prompt, some also have the "forgot username" prompt too. These send email to the email on file, with instructions.) Even though everything else is paperless, W2s, 1099s, etc will come in the mail.

The taxes themselves depends on how he filed previously. If it was something like TurboTax, you might have to work with them. Often you need to know what the last year's return was. If he used a service like H&R Blockheads, they might have something on file. If he files through some other online system, they might be able to help, if he knows who it was.

NOTE: As I mentioned to someone else, federal entities do not honor POAs. If you need a copy of his previous tax return, the Online transcript request on the IRS page has this warning:

"Caution: The Get Transcript Service is for individual taxpayers to retrieve their own transcripts for their own purposes. Use by any other entities is prohibited."

I do understand the need, so proceed with caution. If you use the regular mail method, have dad sign the request. If requesting by phone, he will have to make the request, not you. You may have to lookup how to do a state return or call the tax department for his state to get instructions. No clue if they have any kind of filing extension.

All this may take time, so request an extension by using IRS Form 4868 OR do it online per instruction on
https://www.irs.gov/forms-pubs/extension-of-time-to-file-your-tax-return

This form has to be filed by 4/15/21, but the actual filing would be due no later than 10/15/21.
NOTE: you will have to estimate how much he might owe, report it on the form and pay for that when you file Form 4868. The online request should have instructions and a payment form to submit. If you don't and he owes, there will be late fees and interest charged. If he ends up not owing, you will get that money back as part of his refund. Stinks to tie up funds, so the sooner you can file, the better.

If you have access to his bank account, you can search for debits and credits to see if he has paid or received refunds.

When you have the W2s, 1099s, etc, you can estimate his taxes on paper by printing the 1040 form (note there is a SS calculation worksheet that is NOT part of the 1040 form. Most people only pay tax on part of SS - the worksheet can be found in the 1040 instructions - takes a bit to find the page, but print JUST that page!) This may help to calculate how much he might have to pay with the extension form. Also note that there's an extra deduction for those over 65 (std is 12,550, looks like single over 65 is add'l 1700?)

Hoping you can get all you need... Taxes are NOT fun!

You and dad can order a tax transcript from the IRS:

https://www.irs.gov/individuals/transcript-types-and-ways-to-order-them

You might check around his domicile; he may have hard copies of his taxes. Most peopleP do have. That would be for his older filings. As to his new filings, copies should come to his address certainly for SS and for any banking holdings such as CD earnings. Look at last year taxes and see what you can expect. You are otherwise starting late with getting your POA on file to receive his tax information but you should start now with all entities with his holding. They will want copies of your own ID and of his POA, If you are new at this, and this being first tax year, I don't envy you. My brother was VERY well organized, all ducks in a row, and I still found it difficult. Even this last year, when the IRS decided to issue me TWO EINs to settle his Trust, had been daunting; Covid-19 has made it more so. Start now. Most of us don't "recall" passwords; my guess is that there is a good of them somewhere like a personal phonebook, a ledger book, something other, just full of passworks. There are well over 100 in my own life. And nope, I wouldn't be recalling them. They are written down. Some people actually keep a list in files of their computers.
Wishing you good luck for sure. You may have to delay filing this year. I am hoping you are using a CPA who worked with Dad in past, who will also be of value to you; make an appointment today if that's the case. Hope you'll update us.

How were his taxes done before? Since you have POA, SSA, agencies, banks, et al would send you whatever you need to file. Request on their website or by phone (if you're comfortable reading off SSN, etc over the phone) Since you're handling Dad's taxes, creating and safely storing passwords are up to you. Or just hire a tax preparer.

Do you have last year's return?