You can create and Custom Module or can use your custom theme to implement your requirement.
I assume your using a custom module and I also assume your Custom Module Name is Company_CheckoutCustomtext
You can follow the steps as described below.
Create checkout_index_index.xml under YOUR-MAGENTO-ROOT/app/code/Company/CheckoutCustomtext/view/...
You can use this line to remove email tooltip text.
Instead of using this..
When you add any custom field in Checkout Page need to add data in mainly two tables.
For more understanding download module from GitHub and make changes as per requirements.
Magento2 Checkout Custom Form
Depends entirely on the setup of your extension
See here for example
I add an attribute but also I add a column to the sales order grid and the value set at checkout is transferred
This process is quite involved. Try to understand as much as you can from my extension. See setup and observer event.
Once the ...
As you have using phtml and want to get checkout page, then below code