Free text to a column

Hi all, 

I would need to add free text coulmn to a table (in visualizations) to explain the amounts for some customers. 

Currently I have these columns and the fourth one would be the Comments (free text):  

Customer name / Customer number / Balance 

I have figured out, that I could make a new table with Enter data where there would be only for example Customer name and Comment columns (and via relationships join two tables) and from there I could easily edit the Comments column, but then I would need to fill in the Customer names manually? 

Is there a way that I could make this new table with Enter data so, that Customer names would be exported from an Excel and Comments column could be edited for comments?

Thank you in advance!