Local filters are filters used in Specific selection - unlike the Global filters, they only apply to specific content.
Using local filters, you can filter most of the parameters related to the data you selected, such as:
order (ascending or descending)
and sort by:
Keep in mind that if you will sort, for example, the messages by content: "Hi" you will get even words that have the word Hi in them... for example a word: this
Local filters are applied to the data which you choose in Specific selection:
If you select a local filter, it will be always prioritized against global filters (i.e. if you choose a specific date in the global filter and different date in the local filter, both will be shown in the report)