How to send multiple html forms to store info in a single google sheet tab? multiple forms from single webapp created using apps script

Question

I have created a bootstrap html web page in my Apps Script project. The plan is to publish it and then share with customers. They will login using their user name and password. And then web page shall load with few forms such as Order Request form, Service Request form and Message to CEO; intotal three forms.

I do not have idea as to how I can identify which form is being sent from the client to server.

page.html Partial html -

<form id="form1" name="form1">

  <label for="info" id="info_label">Info</label>
  <input id="info" name="info" type="text">

  <input class="btn" id="button" onclick="onClickFunctions(document.getElementById('form1'))" type="submit" value="Submit">

</form> 

<form id="form2" name="form2">

  <label for="info2" id="info_label2">Info</label>
  <input id="info2" name="info2" type="text">

  <input class="btn2" id="button2" onclick="onClickFunctions2(document.getElementById('form2'))" type="submit" value="Submit">

</form> 

I got this idea from here, but from the questioner's code.

How to I use doGet or doPost to differentiate between two forms?