If you want to prepare for Series C funding then you have to follow some steps to rise your startup:

Step 1: Find your leader investor.

Step 2: Prepare your term sheet.

Step 3: Prepare your official documents.

Step 4: Include pro-rata ownership in a term sheet.

Step 5: Consider the vesting schedule.

All these are the best way to prepare for Series C funding. If you want more information then read this blog post: https://weburic.com/paige-raises-100m-series-c-funding/