Click on a vertex that you don't need in topology:
* Double tap <kbd>G</kbd> to slide
* Slide vertex to the nearest adjacent vertex
* Select vertices (or press <kbd>A</kbd> to select all vertices)
* Press <kbd>M</kbd> *> Merge By Distance* (or enable auto-merge when you're moving them). 

You can also click on a vertex and press <kbd>X</kbd> *> Dissolve Vertices*