Supplementary service

[nykamp]

I do not have an option called supplementary service on my Samsung s21 ultra. So how do I turn on call waiting

[LongHiker · Accepted solution]

@nykamp In that situation you may need to contact your carrier to have it enabled. 

[user_ams007]

It's seems that some carriers like Verizon wireless are removing the call settings from devices even unlocked

[user_ams007]

I am currently using Verizon wireless as my carrier and they removed the settings for Call waiting, even though my Samsung phone is unlocked,