If you are expecting to raise the same invoice to the same client for the same amount on a timely basis, then you can set up recurring invoices that will automatically create based on the timescale you set.
To do this, click on the 'Work > Invoices' tab and then click on the 'Recurring' tab, above the summary table and search box.
Click the button towards the top right of the screen. Populate the information based on the invoice you wish to raise.
Once populated, click the 'Update Recurring Invoice' button at the top right of the screen to save. The invoices will then automatically create, and email if the preference was set, based on the dates and recurrence set.
You can edit Recurring Invoices from the 'Recurring' tab in 'Work > Invoices'.