Set a default template in Numbers on Mac
You can set a preference in Numbers to always open a particular template when starting a new spreadsheet, instead of opening the template chooser.
Create new spreadsheets from a specific template
Choose Numbers > Preferences (from the Numbers menu at the top of your screen).
Click General at the top of the preferences window, then select “Use template.”
The first time you set this preference, the Blank template is selected. If you changed this setting before, the last template you chose is selected.
Do one of the following:
Use the currently selected template: Verify that the name of the template you want to use appears after “Use template,” then close the preferences window.
Choose a different template: Click the Change Template button, click a template, click Choose, then close the preferences window.
After you set this preference, you can still open a new spreadsheet with a different template. Hold down the Option key, then choose File > New from template chooser (from the File menu at the top of your screen).