Plugin Link (External Website) : https://wordpress.org/plugins/miniorange-otp-verification/

Step 1 : Navigate to [Customization] -> [Custom SMS Provider]
Step 2 : Configure as follows
  - Click on 'Set Organization SMS Gateway'
  - Select 'Custom SMS Gateway (Get Method)' on SMS Gateways

  - Gateway url text box, Enter
      https://textit.biz/sendmsg/?id=[Username]&pw=[Password]&text=##message##&reply=Y&to=##phone##
      ( Change [Username] and [password] to your actual username and password. Keep all others as it is)

  - Content Type : Keep blank
  - Authentication Type : No Auth

Step 3 : Click on SAVE and then test the gateway