Difference between sharing rules and manual sharing in salesforce

sharing rules in salesforce
what is owd in salesforceapex sharing vs sharing rules

With sharing rules, one can share records with users who don't have access to the records. Sharing rules allocate access to users in public groups, roles, or Grant internal and most external users access to a user by creating a manual share using the Sharing button on the user detail page of that user. Grant high- Manual Sharing · 1. Full access: Users with full access can view, edit, delete, and transfer the record. · 2. Read/Write: Users can view and edit the record andManual Sharing is used to grant one-off access. Manual sharing can be granted by record owner, any one above the owner in role hierarchy and System Sharing rules to extend sharingaccess to users in public groups or roles. As with role hierarchies, sharing rules can never be stricter than your org-wide The first thing to consider is the object on which you want to share the records. For example, if you choose to share contacts, you will not be able to use