How to manage staff leave, eg vacation, illness, unpaid leave etc

Hi @Valerie Ennis​ 

Here is the list of apps you can select as per your requirement, install it and use it:

• https://appexchange.salesforce.com/category/hr

Here are some apps you can find on appexchange:

• Free: https://appexchange.salesforce.com/listingDetail?listingId=a0N300000016aVIEAY 
• Paid: https://appexchange.salesforce.com/listingDetail?listingId=a0N30000005uqk2EAA

Akash