Where to find this setting
Under Settings > Advanced > Workflow you can turn the Require all approvals when manual appointing setting on and off for your company by checking the box:
This setting applies to cases where one or more approvers are appointed manually for a document, and not to cases where approvers are appointed by workflows:
If the setting is unchecked...
... then a single coworker can give a document its final approval, even if several coworkers have been manually appointed to approve it.
Example: Even if three coworkers have been manually appointed to approve a document, the document is fully approved as soon as the first of the three coworkers approves it.
If this setting is checked...
... then the document is not fully approved until all the manually appointed coworkers have approved it.
Example: If three coworkers have been manually appointed to approve a document, the document is not fully approved until all three coworkers have approved it.