how to remove recurring and all day event option in SharePoint online event calendar?

[Marvin Oco]

how to remove recurring and all day event option in SharePoint online event calendar?

[#2]

one way would be to create a new custom content type that does not include those fields.

Another way would be to customize the display/edit/new forms with InfoPath, SharePoint Designer or PowerApps

[#3]

Agree with Dean here...in regards of customization, I would avoid to use InfoPath or SharePoint Designer....PowerApps is the recommended way assuming custom dev is not an option here