Its something you do daily, and you chart it was well..
When your ovulating you cervix will be HIGH Soft And OPEN very open enough to put a finger tip in...
And, should be clear Cm, or stretchy for fertile mucus.]
This has a lot of info on cervical changes while pregnant and ovulating and pictures (GRAPHIC CERVICAL PICTURES IF YOU DON"T WANT TO LOOK DON"T OPEN)....
https://www.sisterzeus.com/cervob.htm