By default, LibreOffice saves files in the Open Document Format (ODF). However, it also reads and writes files in Microsoft Office formats (DOC and DOCX). If you collaborate with others on Microsoft Office documents, but you use LibreOffice, you can choose to always save files as Microsoft Office files to make it easier to exchange those documents back and forth.
默认情况下，LibreOffice以开放文档格式(ODF)保存文件。 但是，它也以Microsoft Office格式(DOC和DOCX)读取和写入文件。 如果您与其他人在Microsoft Office文档上进行协作，但是您使用LibreOffice，则可以选择始终将文件另存为Microsoft Office文件，以使来回交换这些文档变得更加容易。
There are actually many other formats you can choose from as the default file format, as well. We’ll show you how to change the default file format for saving new files by changing a simple setting.
实际上，您还可以选择其他多种格式作为默认文件格式。 我们将向您展示如何通过更改简单设置来更改默认文件格式以保存新文件。
To begin, open a LibreOffic program (Writer, Calc, or Impress) and go to Tools > Options.
首先，打开LibreOffic程序(Writer，Calc或Impress)，然后转到“工具”>“选项”。
In the tree structure on the left side of the Options dialog box, click the plus sign to the left of “Load/Save”.
在“选项”对话框左侧的树结构中，单击“加载/保存”左侧的加号。
Then, click “General” under Load/Save.
然后，在“加载/保存”下单击“常规”。
To change the default file format for LibreOffice Writer, make sure “Text document” is selected in the Document type drop-down list. It’s the first and default option.
要更改LibreOffice Writer的默认文件格式，请确保在“文档类型”下拉列表中选择了“文本文档”。 这是第一个也是默认选项。
Select the file format from the “Always save as” drop-down list that you want to use as the default for saving new files in LibreOffice. For example, if you want to always save your new documents in the most recent Microsoft Word format, select “Microsoft Word 2007-2013 XML”.
从“总是另存为”下拉列表中选择您要用作在LibreOffice中保存新文件的默认文件格式。 例如，如果您希望始终以最新的Microsoft Word格式保存新文档，请选择“ Microsoft Word 2007-2013 XML”。
NOTE: You can also set the default file format for Calc spreadsheets and Impress presentations by selecting Spreadsheet or Presentation as the Document type, and then selecting the desired file format from the Always save as drop-down list on the Options dialog in Writer, Calc, or Impress.
注意：您还可以通过选择电子表格或演示文稿作为文档类型，然后从Writer，Calc的“选项”对话框中的“始终另存为”下拉列表中选择所需的文件格式，为Calc电子表格和Impress演示文稿设置默认文件格式。或印象深刻。
Click “OK” to accept the change and close the Options dialog box.
单击“确定”接受更改，然后关闭“选项”对话框。
Now, when you save a new document, the file format you specified is automatically chosen in the Save as type drop-down list on the Save As dialog box.
现在，当您保存新文档时，将在“另存为”对话框的“另存为类型”下拉列表中自动选择指定的文件格式。
NOTE: The file will open in Microsoft Office, but it will open in Compatibility Mode. You can still edit the file and save it in Office format, but there may be some features you can’t use unless you convert to the current type of Office document.
注意：该文件将在Microsoft Office中打开，但它将在兼容模式下打开。 您仍然可以编辑文件并将其保存为Office格式，但是除非转换为当前类型的Office文档，否则可能无法使用某些功能。
If you use Microsoft Office Word, Excel, and PowerPoint, and you collaborate on documents with others who use LibreOffice Writer, Calc, and Impress, you can set the default file format in Word to the OpenDocument Format.
如果您使用Microsoft Office Word，Excel和PowerPoint，并且与使用LibreOffice Writer，Calc和Impress的其他人协作处理文档，则可以将Word中的默认文件格式设置为OpenDocument Format 。
翻译自: https://www.howtogeek.com/281166/how-to-change-the-default-file-format-in-libreoffice/