My 401k rollover to an existing ira is not being credited to me because I was part of a retirement plan in 2020 for 3 months. how do i get credit for it?

What do you mean "not credited"?      You should have a 1099-R for the distribution or rollover - what code is in box 7?

You don't get credit for it.  It is just not taxable.  You do not enter it as a new IRA contribution under Deductions.  It is a Rollover not a contribution.  Just enter the 1099R.

Enter a 1099R under

Federal Taxes Tab or Personal (Home & Business)

Wages & Income at the top

Then scroll way down to Retirement Plans and Social Security,

Then IRA, 401(k), Pension Plans (1099R) - click Start or Revisit

If you are filing a Joint return be sure to pick which person it is for.

Don't enter the bank or broker name and don't try to import it.  It is just as fast and easy to manually enter it.  At the bottom pick -  Change How I enter my Form

Then on the next screen pick I'll Type it in Myself

Did not get a 1099r only a 5498 which turbotax does not acknowledge.

box 7 ss tips on w-2 is blank?

You don't enter the 5498.  It is only for your info.  You need to have a 1099R.  Ask the 401K for another copy. 

Yes. I have done all that. However the form I was given from Fidelity is not a 1099r but a 5498 which Turbotax does not let me enter.

W2 box 7 is blank, that's ok.  Leave it blank.  If you think your W2 is wrong ask your employer.

He wanted to know the code in box 7 on a 1099R (not your W2).  You need a 1099R.