@randy provided a great tip under Adding & Reconciling Manual Transactions on generating a unique manual transaction ID here:
But I had no idea HOW TO do this. Made a quick inquiry to MS CoPilot AI, and the instructions on HOW are shown below! For the newbies to Google Sheets, like me, I hope you find this useful. Instructions were easy to follow and worked great!
I just wanted to add a different method for people who are not comfortable working with scripts. With this method, you generate a unique value using a formula, then overwrite the formula with the value. There are 4 separate HEX values generated at random and put together, so there should be next to no chance that the same one would duplicate twice.
Paste this formula into the cell you wish to hold the manual transaction ID:
Then, once the value is there, highlight the cell and press CTRL+C to copy the cell contents, then CTRL+Shift+V to replace the formula with the value. You can also right-click and choose Paste Special > Values only to replace the formula. If you don’t replace the formula with the value, it will update with a new ID every time you refresh.
You can generate IDs for multiple rows at a time, as well. Just highlight them all and do the same thing described above.