Hi @Alex Orlov
Do you know which version of your Office, such as Office Home & Student 2016, Office Home & Business 2019 or others?
I suggest you sign into "My Microsoft Account", check whether there is any Office product listed under "Products you've purchased" like following image shown.

If there is one, then you may install Office via clicking "Install" button. But, before you install Office, please ensure no other Office products installed on your machine. To uninstall Office, you may refer to: https://support.microsoft.com/en-gb/office/video-uninstall-office-dc998d82-350e-432b-a09f-a5225d10b90d.
If there is no Office listed in your account page, please check whether you have a CD with Office installation files.
Or you can use Office for web. On "My Microsoft Account" page, click the 9-dot App Launcher icon in the upper left corner and select the Office for web icon, such as Excel.

- If you do not have a Microsoft account, you can create one.
- Files created via Office for web will be stored on OneDrive.
- Each Microsoft account has 5GB storage of OneDrive for free.
- If you need local file instead of file on OneDrive cloud, you can download it, but you cannot open it locally, because you do not have Office desktop apps.
Hope the information could be helpful to you.
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