I am not sure which official character sheet these fields appear in. In the character sheet that I have seen, those fields look like this:
The free rules include a section at the end that describes each section of the character sheet. The description for those fields are (page 90):
[Cast Cleric Spells Field] Clerics can tick off what level spell they are able to cast, as determined on page 5.
[Cast Magic User Spells Field] Magic-Users and Elves can tick off what level spell they are able to cast, as determined on page 10 and 17, respectively.
These fields are used to denote how many levels of spells you have unlocked. Since the number of dots in your image correspond to the number of spell levels for each Character Class, I believe they would be treated the same way and you would fill in a dot for each unlocked spell level.