Question:

I cannot upload an excel file in Planhat, which file formats are allowed?

Answer:

The following formats are whitelisted:
.pdf, .jpeg, .txt, .doc, .docx, .ppt, .pptx, .xls, .xlsx
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However, the file name must not contain an ampersand (&-symbol), and other similar characters.

P.S.: You can find the option to upload documents in the customer profile, upper right corner.