On my Feodra 22,I have LibreOffice 18.104.22.168 installed from the Default-Repositories.
To insert a new row in a Calc ( Excel ) Document, the INSERT-Menu has a Rows item, which
adds one row.
But when you have to add more data, it is tedious to insert row by row.
It is much easier, but I wouldn't have found this option. See here.
Just select the number of rows you like to insert in the spreadsheet and do a right-click on the
left side of the document, where the row numbers are shown.
In the context-menu click Insert Rows Above and you get a bunch of new rows.