[T-Mobile Samsung Galaxy S6] nolimit78:
This is absolutely not my work. I pulled and tested the following edits from here. I've been looking for this information for a while now and only came across it by chance. Big thanks to tiboric for putting the information together!

I have also tried some of the CSC apps out there that try to help. I didn't find any that worked if anyone knows of some that work post and let me know. I'll edit this OP but for now if you want something that works, this is the way to go!

This is not my work, just sharing.

To enable these you will need root, a root explorer and text editor.

Simply navigate to system/csc/Features.xml and add the corresponding line to the end of the file but before the very last few lines that say </feature> and </Samsung>

(if this file does not exist, create the csc folder in system and a txt file within it then change the name to features.xml and add the correct lines and save) if this does not work you can try the same method with Others.XML in the same folder

*Make sure you make backups of the stock files in case there are issues.*

Enable WiFi calling in phone settings:

<CscFeature_Setting_SupportWifiCall>TRUE</CscFeature_Setting_SupportWifiCall>

Enable native voice call recording(maybe illegal is some countries):

<CscFeature_VoiceCall_ConfigRecording>RecordingAllowed</CscFeature_VoiceCall_ConfigRecording>

Enable shutter sound switch in camera settings(maybe illegal is some countries):

<CscFeature_Camera_ShutterSoundMenu>true</CscFeature_Camera_ShutterSoundMenu>

Enable camera during call:

<CscFeature_Camera_EnableCameraDuringCall></CscFeature_Camera_EnableCameraDuringCall>

Enable manual rotation option in gallery:

<CscFeature_Gallery_AddAutoRotationIcon>true</CscFeature_Gallery_AddAutoRotationIcon>

Continuous music while using camera:

<CscFeature_Camera_CamcorderDoNotPauseMusic></CscFeature_Camera_CamcorderDoNotPauseMusic>

Enable scheduled messaging option in messaging app:

<CscFeature_Message_EnableScheduledMessage>true</CscFeature_Message_EnableScheduledMessage>
<CscFeature_Message_EnableScheduledMsgBox>true</CscFeature_Message_EnableScheduledMsgBox>

Enable exit buttons in default browser:

<CscFeature_Web_AddOptionToTerminate>true</CscFeature_Web_AddOptionToTerminate>

Enable 2nd symbol keys on stock keyboard:

<CscFeature_Sip_UseSymbolInCMKey>true</CscFeature_Sip_UseSymbolInCMKey>
<CscFeature_Sip_EnableSymbolInSecondary>de;en_US;en_GB</CscFeature_Sip_EnableSymbolInSecondary>

Enable VoLTE Support: Thanks to IakobosJ

<CscFeature_RIL_SupportVolte>true</CscFeature_RIL_SupportVolte>
<CscFeature_IMS_EnableVoLTE>true</CscFeature_IMS_EnableVoLTE>

Remove NFC enabled icon in the status bar: Thanks to evonc

Delete line : <CscFeature_NFC_StatusBarIconType>DEFAULT</CscFeature_NFC_StatusBarIconType>

Sort app draw alphabetically:

<CscFeature_Launcher_EnableViewByAlphabetAsDefault>true</CscFeature_Launcher_EnableViewByAlphabetAsDefault>

Remove quick connect and s finder thanks silversurfer9231:

build.prop... changed property ro.product.name value to "zeroltevzw"

If this isn't allowed I do apologize. I'm just trying to spread the good word! Thanks to tiboric for the guide over in the General Section!