A petition starts a district or county court civil suit
Texas Rule of Civil Procedure 22 states that a civil suit in district or county court begins with a petition filed in the clerk’s office. It identifies the document and filing step that commence the suit.
Use the rule for the question it answers
Rule 22 answers how the suit begins. To understand how a document is filed, read the relevant filing provisions, including Rule 21. Other provisions address the petition’s contents and citation; Rule 21a expressly excludes the citation served when a cause of action is filed.
Read the short rule alongside the filing process
The illustration below contains the complete Rule 22 text. It is a starting point for learning the distinction between preparing a petition, filing it with the clerk and arranging the process required to notify the defendant.
The illustrated guide

A petition filed in the office of the clerk.