Yandex Mail lets you attach any files up to 22 MB individually and 30 MB in total per email. You can also insert a link into a file you upload to the Yandex Disk cloud service, which raises that limit to 2 GB per file.
For attachments you receive, Yandex Mail offers a convenient document viewer that displays Microsoft 365 and Office documents as well as PDF files in your browser. When you select a supported attachment, it opens in a separate window. Select Save to Yandex Disk to store it in the cloud.