If there are two or more guests staying in a room and you need to create individual invoice for them there is an option for that in the invoice.

This only works with charges that have already been posted. So if the stay is in the future or a forecast (preview) of charges is being shown then you will not be able to edit it.

Once the charge has been posted you or is being manually posted by you there is an option to choose the Paying Customer. There is where you would select the name of the guest who would be paying for this charge. 

If the charge is already posted click on the field under the Paying Customer column. You will see the dropdown options of the guest names to choose from. Select the guest name who will be paying for this charge and then save the change.

Then, go to the Billed to field, Select the guest name you have assigned the charge to and you will see the invoice will refresh to only show charges assigned to that guest. 

You print this invoice or you can accept payment for the amount shown on the invoice.

If you need to switch the view back to where all the charges are shown just select Everyone from the Billed to field and the invoice will change back to showing all the charges regardless of who it is assigned.