[Tyler Marshall1]

Need it to have apn network settings and i can make it sysyem app myself

[Rukbat]

The APN settings depend on the carrier, so you'll have to google your-carrier apn. You can develop any app there's hardware to support (in other words, you can't develop software to toast bread), and you can develop it to be a systems app. But there already dozens of APN-setting apps in the Play store. (You still have to look up the current settings for your carrier or MVNO [sometimes the MVNO - if you're using one - will use slightly different settings than the carrier uses].)