A simple tag that can be inserted into an Owala lid.  Add text using PrusaSlicer's Add Part > Text tool.  Bending the side tabs down slightly might help the tag sit flush but isn't necessary.  

A sample project is included with a name field already added. 

Slide the tabs under the hinged parts of the lid.  The side tabs should snug around the spring wire and the center tag should push against the lid opening.