Ok so I'll go ahead and make some recommendations for the naive little lamb who comes to this site for the first time, knowing nothing of yuri manga.
My suggestion is to start with some series by Morishima Akiko! She's widely recognized as one of the best and most representative authors presently active, and you really can't go wrong with her.
If you want to read about schoolgirls (a staple of yuri), try Hanjuku Joshi. A 20-chapter manga series, I've read and reread it more times than I can remember. Find it on the online reader here:
https://dynasty-scans.com/series/hanjuku_joshi
If you want to read about adult women, try Romance Girls File. Or perhaps Office Romance: Women's Division. The former is a volume of short stories, the latter an ongoing series following a group of women who work at the same office (with the main character focus of the story shifting every couple of chapters). Links are as follow:
https://dynasty-scans.com/series/romance_girls_file
https://dynasty-scans.com/series/office_romance_womens_division
Or, of course, if you prefer to see and choose by yourself, just visit her author page on the reader and pick whatever catches your fancy from the dozens of mangas and doujins there:
https://dynasty-scans.com/authors/morishima_akiko
Hope you have fun! XD