Nowadays, the majority of smartphones offer dual SIM support. Switching between SIMs for actions like making calls, texting, or accessing 3G is quite straightforward.
To choose a SIM while texting on Sony Xperia XA Ultra, follow these steps:
Step 1: Navigate to 'Settings'.

Access 'Settings'
Step 2: Choose 'Dual SIM.'

Select 'Dual SIM'
Step 3: Choose 'SMS Messages.'

Select 'SMS Messages'
Step 4: Choose the default SIM or always prompt for SIM selection when sending SMS.

Choose the default SIM or always prompt for SIM selection when sending SMS
Wishing you all success.
