Depends, is your Single member LLC set up as an S Corp? If it is not an S Corp then it is a disregarded entity and you file it on Schedule C in your personal 1040 return. So you will need to amend your return to add it.
If you elected your Single Member LLC to be an S Corp you need to file a separate Business return for it. You need the Turbo Tax Business Desktop program. It is a separate program from Home & Business. It is not available to do online or on a Mac. And it will not do your personal 1040 return. You can have both Turbo Tax Business and a personal version (like Home & Business) installed at the same time.
You can buy the Window's version here…..
TurboTax® Business Desktop 2023-2024 | Tax Software Download
Then you will get a W2 and/or a K-1 to enter into your personal return return. So you will need to amend your personal return to add it.
You should not amend until the first return has fully processed and you get the first refund or your tax due payment has cleared.
How to Amend this year
https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-federal-tax-return-curr...
