Step:1 Create a JSON Rendering name as Form as shown below:
Step:2 Make Sure to select the Rendering content Resolver as Sitecore Forms Resolver as shown:
Step: 3 Add the rendering on the Page where you want to show Form and Select the Datasource:
Step 4: Use the below code snippet to render the form
By using following steps you will be able to Render Sitecore Form in Headless.