You can create one invoice for multiple clients at once by linking them to a Billing Profile (Bill To).
When multiple clients are linked to the same Billing Profile (Bill To), all their tasks, packages, and expenses will appear together when you generate an invoice.
Client Name: Aone Toys
Billing Profile (Bill To): Anurag
Client Name: Super Tiles
Billing Profile (Bill To): Anurag
Client Name: Rahul
Billing Profile (Bill To): Anurag
Client Name: Karan
Billing Profile (Bill To): Anurag

A Billing Profile (Bill To) cannot be assigned to another Billing Profile or to another client.
(Billing Profiles stand at the top and cannot be nested.)
A client cannot be its own Billing Profile.
(Self-billing profile is not allowed.)
If a client is already linked to a Billing Profile, it cannot become a Billing Profile itself.
(Once a client is in a Billing hierarchy, it cannot act as the billing head.)
Go to the Clients menu.
Open the client you want to edit.
Click Edit.
Select a Billing Profile (Bill To) from the dropdown.
Click Save.
Go to the Clients menu
Select the clients you want to update
Click Change Billing Profile in the action bar
Select the Billing Profile and Save.
Auto Billing works only at the Billing Profile level.
The linked clients cannot enable Auto Billing individually.
All linked clients follow the Auto Billing schedule of the Billing Profile.
Only completed tasks will be invoiced.
Packages and expenses are not included in Auto Billing.
The amount must be entered in the Assigned Services for the task to be billed.
You can filter clients based on Billing Profile in Clients and Client Reports.