Can a tent be evicted with a 3 day written notice if there is no lease agreement or agreement of any kind?

In my state, the landlord files a "dispossessory" with small claims (magistrate) court. The landlord and tenant meet in court. The judge makes a decision. Lack of written agreement such as a lease or rental agreement makes for complications. It's one person's word against another's. If possible, get the advice of a lawyer.

Depends on the state and the reason, for non payment the landlord can give a 3 day pay or quit notice, but they don't move, the actual eviction will take more time. You have to file in court, they have to serve the person, there has to be a hearing, and then a date for them to move out will be set.

For example in some states a family with a child in the middle of winter may be additional time to move, A elderly or sick person may get extra time by the court.