Transaction Log Shipping Removal, Backup and Drop Database
You should first remove logshipping using below procedure. You can use both TSQL and SSMS for this
To Remove Log Shipping
On the log shipping primary server, execute sp_delete_log_shipping_primary_secondary to delete the information about the secondary database from the primary server.
On the log shipping secondary server, execute sp_delete_log_shipping_secondary_database to delete the secondary database.

Note
If there are no other secondary databases with the same secondary ID, sp_delete_log_shipping_secondary_primary is invoked from sp_delete_log_shipping_secondary_database and deletes the entry for the secondary ID and the copy and restore jobs.

On the log shipping primary server, execute sp_delete_log_shipping_primary_database to delete information about the log shipping configuration from the primary server. This also deletes the backup job.
On the log shipping primary server, disable the backup job.
On the log shipping secondary server, disable the copy and restore jobs.
Optionally, if you are no longer using the log shipping secondary database, you can delete it from the secondary server.
To remove Log Shipping using SSMS
Right-click the database you want to use as your primary database in the log shipping configuration, and then click Properties.
Under Select a page, click Transaction Log Shipping.
Clear the Enable this as a primary database in a log shipping configuration check box.
Click OK to remove log shipping from this primary database.
After logshipping is removed drop databases.