when text messaging was invented, there was no way to send emojis. it wasn't until messengers like WhatsApp came along that the many colourful faces became popular. technically, however, it was not possible to send emojis with an SMS. although sending emojis is less of a problem nowadays, it can sometimes happen that emojis are sent as question marks due to an incorrect setting. in this case, the input mode must be changed on the Samsung device.

To send emojis you need to select the Unicode mode. Alternatively, it is also sufficient to use the Automatic mode, where the Samsung device itself detects when an emoji is present in the text and selects the correct input mode accordingly.

Android 10 (One UI 2.0)
Step 1:  Open the  Messages -App
Step 2:  Open the  menu
Step 3:  Open the  Settings
Step 4:  Tap on  More settings
Step 5:  Tap on  Text messages
Step 6:  Tap on  Input mode
Step 7:  Choose between  GSM alphabet ,  Unicode  and  Automatic
  1. Open the Messages-App
  2. Open the menu
  3. Open the Settings
  4. Tap on More settings
  5. Tap on Text messages
  6. Tap on Input mode
  7. Choose between GSM alphabet, Unicode and Automatic

Samsung Instructions