I'm a retiree living in Thailand. There does not seem to be any way that I can enter my address, nor my phone number. What can I do?

[mesquitebean]

On what screen/section?   Are you in the Personal Info section on a screen asking about your current mailing address?

[mesquitebean]

In the interest of time, I went ahead and left you an answer below.  I assumed that is the screen you are referring to.  If that's not the right section, report back.

[mesquitebean]

If you are in the Personal Info section at the screen which asks for your current mailing address,  you have to first indicate the "type of address" as "foreign country."   Use the dropdown menu for "type of address."    (see the screen image below)

Once you indicate the address is foreign, then the data fields change, and you can enter the country and the international postal code, etc.

You won't be able to enter a foreign phone number.  The phone field will only allow a USA type phone number.  You can leave it blank.  It's not required. The IRS will not phone you for initial contact anyway.