1，2，3 - 完全可能。

4 - 不是这样。 Google Apps脚本不支持将工作表转换为Excel格式。但是，您可以生成一个可以被Excel或其他电子表格程序理解的CSV文件，并将其作为附件发送给您。

生成CSV包含在其中一个Apps脚本教程。请参阅保存选定范围从 教程：与您的文档列表进行互动 。

来自云端硬盘的文件在 MailApp.sendEmail（）。

I have a script that turns a submitted form into a PDF and emails it automatically but I can't seem to get my head around if it is possible to implement a function i would like: -

1. User fills in Google form
2. Submits form
3. This creates entirely new spreadsheet based on same headers from the form
4. Emails thie spreadsheet as an .xlsx attachment automatically to a specific email address

Is this possible? I feel like I am missing a simple way to do this but I am having a moment of noobishness! :-)

1, 2, 3 - all quite possible.

4 - Not as such. There's no support in Google Apps Script for converting a Sheet to Excel format. However you could produce a CSV file which would be understood by Excel or any other spreadsheet program, and email that as an attachment.

Generating a CSV is covered in one of the Apps Script tutorials. See Saving a selected Range to a CSV file from Tutorial: Interacting With Your Docs List.

An example of attaching files from Drive is provided in the documentation for MailApp.sendEmail().