Hello Koxul Comercio Electronico,

In Odoo 14 by default export file with extension .xlsx

Please Export a spreadsheet with xlsx extension you will get your answer.

Thank you!

Regards,

Email:      odoo@aktivsoftware.com  

Skype: kalpeshmaheshwari

Hello Koxul Comercio Electronico,

If you download the Odoo Spreadsheet you create from the Document module, the file it download is a text file which contain the special format and has no file extension. 

The Odoo Spreadsheet allow you to export the file into excel or csv like any other Odoo module, however, please do not expect it to be Excel compatible as the data section of the files are special  formatted. 

Regards

Jason