You can invoice as many jobs as you wish, whether they concern the same client or different clients.
When you're in your list of jobs, simply select all the jobs you would like to invoice and click on Actions > Create invoice(s).
The system will then open a popup containing all the invoices you just created.
You can click on the icon on the right to open these invoices in a new tab. All these invoices will be added to your list of invoices, and the corresponding jobs will automatically be marked as 'Invoiced'.
If you defined some jobs as non billable:
Jobs can be defined as 'non billable', meaning that no estimate will be calculated and that these jobs won’t appear on any invoices. In the job details, there is an option to define the job as non billable. (See this article: https://help.lsp.expert/en/articles/1918141-what-s-the-non-billable-option-for).
That's not a problem with the 'bulk invoice' functionality explained in this article. Just select all your jobs (even the non billable ones) and click on Actions > Create invoice(s). The non billable jobs will simply be skipped by the system.