Yes, when you select the option to amend your original return, the program will direct you to Form 1040-X, which is the form you're describing.
You should wait until your original return has been completely processed by the IRS and any refund has been received. Don't amend just yet. Additionally, you'll need to print, sign and mail your amended return. Amended returns cannot be e-filed.
The TurboTax FAQ below will instruct you specifically on amending your 2018 return. Please follow the instructions carefully.
https://ttlc.intuit.com/community/amending/help/how-do-i-amend-a-return-in-turbotax/01/27579
*** I am NOT a tax expert. I am a seasoned TurboTax user, and volunteer to provide assistance to TT users. Nothing I post is to be considered TAX ADVICE; I bear no legal liability for responses.***