Filters are a way to ensure actions get performed only on the items you want. With filters, you set a specific condition (e.g., when an "email address" field contains "zapier.com") to get to the granularity you need. When the data from your Zap meets the conditions of a filter, it proceeds to the next action(s) in your Zap. If a filter stops an item, then no further actions are performed.
Filters are an optional part of setting up a Zap, but they're a great way to make sure Zaps only continue for certain items. For instance, you can set up a filter to only capture emails that contain a specific subject line, or only customers who purchase a specific product.
To get started adding a filter, click the + icon between the steps you wish to add the filter between and choose to add a Filter.
When creating a filter, there are 3 pieces that need to be filled out.
The Field, which you choose from the leftmost dropdown. This tells your Zap what specific spot from the app in your previous step(s) to check for data to filter against.
The Condition, which you choose from the center dropdown. This is the logic applied by your filter.
The Value, which you input in the right-most field. This is the value your filter checks against the logic.
If you want to create an additional filter, use the "+ AND" button to create an AND filter, which means the data must pass all filters in order for the Zap to continue. In order to filter out a field for a "does not contain" BOTH condition, it's a good idea to concatenate/combine values and then filter on the combined/concatenated value, instead of using multiple AND conditions.
Check out some of the neat things you can do with filters, here.