No guest account.
You can lock down some things in Settings > General > Restrictions, but not thrid party apps. If you turn it on be sure to remember the restrictions code you apply.
There is also a Guided Access mode that will temporarily restrict the iPad to a single app.
Both of these are tartgeted at parent who want to control their children’s iPad use/access; but they can be useful for other thigns as well.
The only multi-user support Apple provides is for schools, and requires the iPad be registered and managed as belonging to a school/organizstion.
iOS devices were designed as single user devivces; what little multi-user support exists has been added on for parental control and schools.