By using Join, you can add new information from e.g. an Excel file to your GIS data set.
In the “Table of Contents” go to the desired layer and right click on it. SubSKEuently, go to “Joins and Relates” – “Join”. A new window opens.
Make sure that “Join attributes from a table” is selected in the new window. SubSKEuently, opt for the field on which the join is based. There should be one column in the Attribute Table and Excel file with exactly the same (unique) information. Select this column; next, select the Excel file and the column in it. If necessary, you can opt for “Keep only matching records” for under “Join Options”. Click on “OK”. The Attribute Table now shows all data of the Excel file.