Is there a way to edit the file that was created after a mail merge?

I am creating labels, and choosing print to file, and would like to edit that file before printing. However the file is read only. I do not have the “edit file” icon available and Edit → Select text is grayed out. I have some addresses that are too long for one line and would like to either change the line breaking on that one label. I would also like to be able to fill in blank labels for the return address. Trying Save as with a new name or file type does not change the read only problem. Alternatively, is there a way to create labels without using a merge? Everything I’m finding details using a merge. If there was a way to just load the Avery template and fill in from there, it would take longer, but would be a work around. Thanks.