Need macro advice! Saving longer numbers as strings to show all the characters

Desktop, Excel 365 Build 19929.20106 Click-to-Run, Beginner

We have a macro that generates new files using a list of data. Sometimes that data is completely numerical with over 15 digits. Excel keeps reformatting these numerical entries using scientific notation, which screws up the output files.

Right now I have to manually check the output files and reformat the affected ones so that all then hidden characters are shown.

Can someone please advise on how I can update the macro to automatically convert these numbers into strings that show all the characters? The data is of variable length, but I'm pretty sure it's always under 20 characters.

This problem only affects one cell of the output file. Everything else is generated without issue.

It's basically the problem of "how do I make Excel macro copy-paste the entire FedEx tracking number correctly" but the data isn't consistently 16 characters and is frequently alphanumeric.

EDIT: I'm open to even stupid and booleg solutions like "add a hidden text character before transferring the data" to force this to work. The output files are basically just printables. I just don't know anything about macros and do not have time to learn.