Settings
Before you can place multiple projects on an invoice, it's important to configure this correctly in the settings. Go to Settings > Invoices > General invoicing settings. Here you will find the option 'Multiple projects per invoice'. If this is checked and saved, it will be possible to place multiple projects on one invoice.
Multiple Projects on an Invoice
If you now have multiple projects (for one debtor) and want to put the services from these projects on a single invoice, you can do so via the invoicing module. Under 'To be invoiced', you will see the amounts ready for invoicing per project. Select the projects you want to put on one invoice, click on Actions > Generate Drafts > and check the 'Merge onto one invoice (if possible)' option. Then click 'Generate Drafts'.
Please note: You can simply select all lines under 'to be invoiced' at once. Only if they are projects with the same debtor will these lines automatically be placed on one draft invoice. For the other projects, separate draft invoices will be generated.