Hi @Anonymous
Thank you for posting.
According to your description, you would like to send email based on excel file but are confused to some input while configuring flow. Here are the related information for your reference:
“Table”
Table is created in excel in advance while we preparing excel file. This is a identified part for which sheet you want to use from excel file. We can create table

Since you didn’t mention about your actual requirement and action you want to use, I will take ‘update a row’ action as example which contains ‘table’, ‘key column’ and ‘key value’ area together.
After we set up table in excel, you will be able to select ‘table’ which is detected by flow automatically.

For ‘key column’ and ‘key value’, they are used for identify unique value from your excel.
- Key Column: It can be whatever column you want in a table that can serve as a reference to indicate what is the row that will be modified. Make sure that it has unique values, because an error will be generated if duplicate values in this column are generated.
- Key Value: It is whatever unique value you want in the Key Column to indicate what is the row that you want to update.
Example: If you have a table with two columns: Column1 and Column2 and Column1 has numbers from 1 to 5 and you want to update the row that contains a value of 2 in Column1, then "Column1" is your Key Column and the value "2" (without the quotes) becomes your Key Value.
If you still have trouble building a flow, just explain me your requirement including 'information format in excel'/'information wants to be sent via email', I can help you or provide some tips for you.
Hope the content above may help you.
Best regards,
Anna