The choice between placing the hamburger menu in the top-right or top-left corner of a header depends on the platform and user behavior:

• Android Apps: For Android apps, it's best to place the hamburger menu on the top-left which aligns with Android user expectations and enhances usability.
• Multiplatform apps: Designing for multiple platforms may involve a trade-off. Placing the menu on the left suits left-to-right language users and their F-shaped reading pattern. However, since the hamburger menu often hides secondary features, placing it on the right can reserve the left side for more critical content. This position is also more accessible for right-handed users navigating with their thumb.
• iOS apps: In iOS app design, instead of a hamburger menu, consider using tab bars, navigation bars, or other iOS-specific elements for navigation and content organization.