Hello ; Please to check the following link for details about differential pair routing : [https://docs.easyeda.com/en/PCB/Route/index.html#:~:text=EasyEDA%20provide%20a%20easy%20experience%20for%20the%20differential%20pair%20routing.&text=You%20must%20make%20sure%20the,Tool%20-%20Design%20Rule”%20first.&text=While%20routing,%20when%20change%20layer,%20editor%20will%20add%20vias%20automatically.](https://docs.easyeda.com/en/PCB/Route/index.html#:~:text=EasyEDA%20provide%20a%20easy%20experience%20for%20the%20differential%20pair%20routing.&text=You%20must%20make%20sure%20the,Tool%20%2D%20Design%20Rule%E2%80%9D%20first.&text=While%20routing%2C%20when%20change%20layer%2C%20editor%20will%20add%20vias%20automatically.)