My number is not showing on other's phone when I call

To check possible reasons, do the following:     

Step 1: Check if the receiving person has a caller ID. If other party or the receiving line has caller ID and the number is not showing, proceed to Step 2. 

Step 2: Check if the calling line ID is restricted.  

Step 3: Try to make outgoing calls and check if the number is still withheld. 

Step 4: If the number is still not showing to all, you could have opted for a caller ID restriction plan or withheld number plan. You need to contact the Network provider to remove the Caller ID restriction plan.

How to check if calling line ID is restricted 

Note: There is no certain function that you can withhold your phone number to a certain person.

(The steps below apply only to Jelly Bean OS)     

Step 1: On the Home Screen, tap Phone.        

Step 2: Press the left menu button and tap Call settings.      

Step 3: Under Call settings, tap Additional settings.      

Step 4: Under additional settings, tap Caller ID.       

Step 5: On the pop up screen, select Show number.       

Step 6: A pop up will appear saying Updating settings. Once completed, the caller ID will be changed to Number displayed in outgoing calls. 

How to turn your Caller ID On/Off on Android 9 OS.

Step 1: On the Home Screen, tap Phone.

Step 2: Press the left menu button and tap Settings.

Step 3: Under Call settings, tap Supplementary services.

Step 4: Tap Caller ID to turn it on or off.