This point is often misunderstood included by Freemasons themselves.
The highest degree in Freemasonry is the 3rd: Master Mason
There is no “higher” level than the 3rd. It is the degree needed to take part in masonic work, for instance chairing a lodge meeting.
A Master Mason is as high as you can get as a Freemason, after having been initiated as an Entered Apprentice, and then trained as a Fellow Craft.
There is no need or obligation for any Freemason to go any further if they do not so wish. It does not make them lesser Freemasons.
Further degrees
Some orders, like ours, offer a path that consists of further degrees.
They are not “higher” than the third degree, but they can be seen as “further” or “deeper”.
We “work” the “Ancient and Accepted Scottish Rite” from the 1st to the 33rd degree.
Other orders may have another degree structure.