Purchase a local CD from your nearby hardware shops
When I needed that, it was really hard to find on internet tbh
Since I presume you aren't referring to a legal CD, there are torrents literally everywhere

Is there any safe place to get the trial version?
As safe as it gets..
Link.I actually have multiple subscriptions.
office365 is really nice, you just sign in to your account and can download office on up to 5 devices at a time directly from their website.
If you can't purchase office, torrents are the easiest way.
Download activated/cracked version, enjoy on unlimited devices
- PM if you need torrent links too :3