Start by investing time in some training resources. There are a number of options--including free videos in You-Tube.
But to answer your question,
If you have a field in your table that records the name of the city, you can enter find mode and specify the name of the city, perform the find and then you have a found set of all invoices from that city.
This is just one of many possibilities, but the simplest for a beginner to do.
Is there any way I can enter each date 's sales and city and have another table then sort the city's individually? I'd apppreciate any help thanks.
I repeat my suggestion that you invest in additional training.
A "Table" in FileMaker terms is something that you define in Manage | database | tables.
From what I see here, that additional table is not needed though a table with just one record for each city could be used if you defined a relationship to match records in the original table to it by city.
But you can also just set up a summary report and sort your records by the city field. Such a report can list each individual record or be set up to have just one row of data for every city. A summary field, if needed, can be used to compute a total over multiple records in your report as well.