Welcome to the Airtable community!
Airtable has different methods of propagating data from one table to the next.
The most common method uses linked records. Records in table1 are linked with records in table2. You can then use lookup and rollup fields to automatically show data from one table in the other table. However, if you add a new unlinked record, any links would not be automatically made.
Other methods of passing data between tables are possible using automations or integrations.
If you need more information, can you give some more specifics on your use case?