Why are you even using a userform text box for this? Surely a combobox would make more sense? You could then have two columns in the list box, one for the number, the other for the description. You can choose whether or not to display the second column, if the users know what the numbers refer to. If you have the list in Excel, you can read the values into the listbox. See example attached. Save both items in the same folder for the list to work.
I also suggest using content controls rather than bookmarks as they are much less likely to be accidentally deleted. see
https://www.gmayor.com/insert_content_control_addin.htm