Go to Configuration → Approval Process → select the particular approval process → Edit:

Next, in the Approval process type section, we define the exact acceptance path.

When we select Defined approval process (not automatic acceptance) in the Approval process type, we can define the Approval step(s)

As you can see in the screenshot above, we add subsequent approval steps or approvers by using the plus (+) button.

We can add one or several approval steps, specifying one or more approvers in each. If there are several approvers at one approval step, only one of them needs to accept the request (parallel permissions).

The approver can be:

In the screenshot above, at the 1st step of acceptance, the application is sent for approval by the direct manager and John Smith - only action from one of them is required.

After acceptance, the application is sent to Lawrence White for approval in accordance with the second step.

Finally, after Lawrence's approval, the application is sent for acceptance by the HR department (all members of the HR team) - acceptance by one of the team members is enough for the application to finally obtain the status Accepted.

The approval steps can be freely configured in relation to the type of request being submitted by using the Add alternative process button: