Besides doing it on a lease level for each individual lease, you can also renew leases in batches.
Step 1: Click on Tenants and Leases--> Batches--> Lease renewal batches
Step 2: Click on New Lease Renewal Batch
Step 3: Select the dates and then click OK
Step 4: Select all the leases and click OK
Step 5: Click on a property that has multiple items(leases)
Step 6: Click on Batch items tab and select all the units
Step 7: Click on Actions --> Approve Batch.
Step 8: Click an Actions --> Execute.
Now, when the lease reaches its expiry date, it will automatically be renewed.