My phone number is shown as a Spam number to the recipient of my call
We regularly receive calls from our customers that their customers receive warnings for possible spam calls on their mobile devices (usually OnePlus and Samsung). This is because those users may be using Smart Call.
Samsung
Samsung uses Smart Call. As a solution for Android, you can fill out the Hiya form and create a ticket for them to fix this.
OnePlus
On a OnePlus device, you need to adjust a setting on the phone itself. CallerID needs to be disabled. The solution varies depending on the type of device.