Check that you have the necessary permissions to view and manage Functions in this Function App. You can go to IAM and check your assigned role on the function app
Also check that your Function App is deployed correctly. If the deployment is incomplete or incorrect the option may not appear.
If the above is not the case you can also try clearing your cache, refreshing the page, or using an incognito/private browsing window to see if the options remain the same and its a UI issue
To create a trigger, see: https://learn.microsoft.com/en-us/training/modules/execute-azure-function-with-triggers/?source=recommendations
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Regards,
Abiola