Keep these income limits in mind;
https://www.fidelity.com/retirement-ira/contribution-limits-deadlines
You’re likely over the income limit to make a deduction on a TRADITIONAL IRA contribution. HOWEVER you may make a NON DEDUCTIBLE contribution to a TRADITIONAL IRA. You make this non deductible by filling out a form 8606 at tax time. This money which you have contributed to a TRADITIONAL IRA can then be rolled over into a ROTH IRA. There is no income limit on doing this and is your BACKDOOR ROTH IRA contribution.
So;
-Contribute to a Traditional IRA
-Don’t take a deduction at tax time (assuming you’re over the income limit to do so)
-Roll to a Roth IRA
Extra tip; roll the money from the TIRA to RIRA sooner rather than later. Also leave it as cash when you contribute it PRIOR TO the roll over. This will avoid gains on the money while it sits in account that make your tax life a little bit more difficult come April 15th.
Another tip; open the TIRA and fund it, then close it after you roll it over. Repeat annually. It makes accounting MUCH easier. If you already have a TIRA open with a balance, you may want to see an accountant as a new set of rules called the “pro rata rule” now applies. If you don’t already have a TIRA with a balance, disregard and follow steps 1-3 above.
I find keeping all of this stuff in house a Fidelity to be the easiest way versus having multiple accounts at multiple brokerages. Fidelity is competitive with their commissions and expense ratios on their funds when compared to everyone else. I don’t see a huge advantage to going through the PITA of transferring money via paper check, personally. That’s your call though!