If you have created rules and they are not working for you, then you can check how the rule is setup.

After checking all fields and settings with the suggestion below, run the "Test" button to see which emails will match the rule. This will not process the rule, but just show the results.

You can also tap on "Run now" to run the rule. Note: emails that have already matched a rule will not be processed a second time. So if you add more actions, the new actions won't be applied. You will need to create a new rule. You can copy the search criteria from the action menu to paste into a new rule.

To see what rules are processed when you receive emails, open the left side panel - Smart Folders - History. There you can see when the emails are received and what rules are processed for each new email.

You can also select the "History" action in the action menu to show the history of this rule.

Checking rule settings:

Open the rules screen and tap on the rule to edit it View

In the top of the rule edit screen, check which email accounts and folders the rule uses. Tap on the cog button to choose accounts and folders, or choose 'Favorites' for all of your favorite accounts.
Also check when the rule runs. Usually you want to choose 'New emails' for the 'When to run' option, to process emails when you receive them. You can also choose to run the rule daily or weekly.

In the rule settings, also check that the rule is marked active.

Check that any other rules do not have the "Run other rules after matching" set in the rule settings. Rules that match and have this setting turned on will not run other rules.

Next, check the actions. If you have an action to move to an email folder, check that the folder exists by selecting it again.

In the Search section, make sure you use the correct 'and' or 'or' linking of the fields. using 'and' will require that ALL fields match before the rule is processed.

When comparing text in search fields, make sure you use the correct comparison. Using 'contains' is usually a better option than 'equals'. Equals requires an exact match with the text field you are comparing it to. Upper case/lower case does not matter in comparisons.
If you use commas in the search field check if you want to have the values split or combined. Use the "Split up fields with commas" option in the rule settings. When you want multiple values split by commas, the values will use the "or" comparison for each item.

For date fields, make sure you are using the correct 'Before' and 'After' comparison. Before means the search field will match when the item date is older than the date you entered in the search field.

If you want to check multiple search fields, such as searching for when an email contains 'product' or 'service' then you need a search field for each word. Do not add multiple words in a single search field.
eg. "Subject - Contains - product,service" will not work.

You need to create 2 fields,
"Subject - Contains - product"
OR
"Subject - Contains - service"

If you want to mix 'and' and 'or' search field joins, then you can use a 'Nested search' for the opposite join type. eg, the main search uses 'and' and the nested search uses 'or'. View