How to use the fill-in rule in mail merge

[@DangNguyen-fp1uf]

Very useful and easy to understand, thank you so much!

[@C0ntiChannel]

@Dang Nguyen You're welcome. Glad it was useful to you!

[@quentinjacobson863]

hi, why my mail merge saving the fill in the same for every letter even though I didn't click on the ask once? and also, can you tell me how to use fill-in prompt and add a merge field in it? thank you so much if you can help with the questions.

[@sherekhan90]

So who creates the fill-in field and who fills it in later? Is it the same person? And who is the end user? The person who creates the letter, or the person who receives it? Confusing.. Why not just put the data there when you create the document the first time? Or is it that first you create a document and later when you are sure of the specified data, you fill it in?