erasing all content and then recovering

If I erase all content from my macbook pro before sending it in for repair (yes, I will do an external time machine backup, and test it and turn off find my mac):

Do I need to use the backup if all runs smoothly, or can't I just sign in to my apple id when I get the computer back (or a new one) and let it populate?

Will my other apps appear, like adobe suite, word etc?