By default, you can allow files of size upto 20 MB to be uploaded using the File Upload field or Audio/Video Upload field.
To allow file uploads above 20 MB (upto 1 GB),  

1. Upgrade to our Premium or Zoho One Enterprise plan.

2. In your form builder, go to Settings > Manage Form Attachments.

3. Choose Zoho WorkDrive and select the Manage Manually option to create and manage folders manually.

4. Once you set up your team in Zoho WorkDrive, select the desired folder to map the attachment fields to it and click Add.

5. Select the Allow Uploads above 20 MB option to allow uploads up to 1 GB. When you select this option, the attachments will not be processed by Zoho Forms and will be directly stored in the configured Zoho WorkDrive folder.
   

6. Click Save.
   
   
   
   

7. Then, configure the maximum file size in the field properties as required.
   
   
   
   
   

Note:
1. Form attachments of any size will not be supported in PDFs, Merged Documents, Email attachments, and Integrations.
2. Large file uploads option is not supported for forms with Smart Scan fields.