Generating UTMs isn’t difficult - HubSpot has a tool for it and there are lots of online templates out there.
The problem is many of the templates leave blanks on unpopulated values - you don’t want a link that contains &utm_source=&utm_term=, which could cause errors or wipe existing values.
The other, bigger problem, is consistency. For UTMs to generate accurate reporting and reliable attribution they must be consistent. That means limited, restricted values for Medium and Source and standard naming conventions for campaigns.
Once those are in place you can build a custom attribution system and consistent reports. But it means you need your team on the same page with your UTM standards, or have one person in charge of generating them.
Either way, I built this basic UTM Generator Template in Google Docs with these needs in mind. Simply make a copy to use - then drop in your destination URL and fill out the rest of the columns as needed (note the restricted values in the Medium column), then copy the link.
Need help with attribution or reporting? Reach out and schedule some time with me.