I’m new to the community, maybe 15 minutes new, and wonder if my excel and word documents can be copied to the Libre programs.
Yes, the vast majority of your files will be well received by this office suite. You can use your old files “as is”. You can open each of your files and save it in the format recommended for this office suite, Open Document Format, ODF. You can perform automatic file conversion by choosing File - Wizards - Document Converter.
Some problems may arise (may! not necessarily arise!) with files that contain VBA macros.
Files transfered or copied to an application is totally unclear , but I guess you mean if you can EDIT your excel and Word documents in LibreOffice.
A simplistic answer is YES with some CAVEATS ie. provided the documents are not too complex in their formatting and you don’t have to collaborate on those same complex documents with other users using Microsoft’s products.