Feb. 1 Paid $6,000 for a one-year insurance policy.
Insurance expense debit 6000/prepaid insurance credit 6000
Correct?

Mar. 24 Received $5,000 cash in advance from Denton Company to provide travel services in the near future.
Cash debit 5000/unearned revenue credit 5000
Correct?

Mar. 17 Completed travel services to customers for $12,000 on account.
Accounts receivable debit 12000/revenue credit 12000
Correct?

Feb 1 your Debit will be to Prepaid Insurance and your Credit will be to Cash.

Your other entries look good.

Thanksss :D