I want to merge text documents into another document to have one file. I am having trouble getting specific instructions to do the merging. I have LibreOffice 6.3.
Open your file where you want to merge.
Move the cursor to the desired position in the document.
From the menu, choose
Insert> Paste Text From File....
In the Insert dialog box, select the desired file and click Open.
You can do this any number of times.