[Edited to add: this answer applies to an inherited IRA, not a pension. Pensions are different.]
Your RMD is the minimum amount you are required to withdraw. It depends on your age and the balance in the account. Your broker can tell you what your RMD for 2021 was. You can always withdraw more, but if you withdraw less, you may pay a substantial penalty (there is a way to request a waiver). Its not a single special transaction; for example, if your required minimum was $4000, you could withdraw $4000 all at once, or $333 per month, or anything else, as long as the total for the year was equal to or more than your required amount.
Turbotax asks because if you withdrew less, you may owe a penalty, and even if you withdrew more, there are some things you can't do with the part of your withdrawal that was used to satisfy the minimum requirement.
Now, do you even have an RMD for an inherited IRA? That depends on when the previous owner died.
If they died in 2019 or earlier, you have three choices on how to withdraw the money:
1. all at once (no RMD required)
2. all within 5 years and close the account (no RMD required for years 1-4)
3. spread out over your lifetime (you must withdraw at least a minimum amount each year)
If they died in 2020 or after, you only have one choice. You must withdraw all the money and close the account within 10 years. There are no withdrawal requirements for years 1-9 as long as all the money is withdrawn by year 10.
