Ask three separate questions
Can we join the same session? Can I continue my progress on another device? Do I need to buy the game again? Those are three distinct questions, and a single “cross-platform” label can leave two of them unanswered. Look for a direct explanation from the publisher for your exact platforms and the mode you plan to use.
Cross-play usually describes multiplayer across different platforms. Cross-save or cross-progression describes carrying a save or account progress between places you play. Cross-buy describes purchase entitlement across products or platforms under a particular offer. None should be inferred from the presence of another. A game can also use different rules for campaign play and a competitive mode.
Get the edition right
Begin by comparing the full name shown on each player’s title screen or store receipt. Java and Bedrock editions of Minecraft, for example, do not join the same ordinary multiplayer servers according to Mojang’s edition guide. That distinction can matter more than whether two people both own a Windows computer.
Write a brief group note with each device, edition, current game version, and intended mode. This gives you useful information to compare against official support. It also prevents buying a second copy in the hope that a vague platform label will solve the problem.
Link accounts carefully
Publisher accounts can connect progress across devices. Epic’s guidance for Fortnite explains that the relevant platform accounts need to be linked to the same active Epic Games account. Check which account holds your existing progress before changing anything. Account linking is not a promise that two separate histories will merge.
Virtual currency can have additional rules. Epic specifically flags V-Bucks as an exception to its general purchase and progress guidance. Read the relevant wallet policy rather than treating an item library, a save file, and a currency balance as the same thing. Do not unlink an account just to experiment with where an item appears.
Run a short connection check
Update both games, compare the account names you are adding, and create the simplest supported session before planning a long evening. If an invitation fails, note the precise error message and whether joining from the other direction changes the result. Test one change at a time so you know what actually helped.
For a family session, review platform privacy and age settings with the person managing the account. For troubleshooting, use the publisher’s current support route. Never share passwords, recovery codes, or a complete payment receipt in a public help thread. A little preparation before everyone sits down is often the best multiplayer upgrade you can make.