My company has a Macbook that the user left, we wish to reset or erase it, but it said it link to a apple ID

The device is locked to the previous user's Apple ID account.

Activation lock can be removed only by the following methods, as described in How to remove Activation Lock

• Entering the Apple ID and the password with which it was set up.
• The previous owner removing the device from their list of devices at www.iCloud.com/find.
• Start an Activation Lock support request which requires proof of purchase - a sales receipt.

If the Mac is the property of your company the sales receipt might be in your possession somewhere?

Your company's IT depart should have procedures in place to deal with this. That's one reason they exist.