As an Admin, you can reset a user's password in multiple ways to allow the user to regain their access to the platform.
Navigate to the user's profile via Admin > Organization > Users and click to "Edit" the profile. Scrolling down, you will find a field marked Password - here you can enter a standard password which must also fulfil the password requirements. An example can be: Example123!
Passwords must be a minimum of 8 characters and must include at least 1 letter(upper or lower), at least 1 number (0-9) and MUST CONTAIN at least one of these special characters: (!$#%-_*"€()=?^~)
The other possible way is a bit more tricky and should only be used when the user appears to be Pending, meaning an email has already been sent to the user but they are still unable to access the platform. Simply navigate to Admin > Settings > Mail Template & History > Mail History - find the activation email sent to the user by using the Search field, Preview the email and click on the link to Activate. A page will open where you will be able to enter a standard / generic password and then click to Activate the user.