Since the inception of testing, the problem of testing on mobile devices existed. Until, emulators and simulators came into scenario.
Basically simulators and emulators are the same, simulators are the replica programs provided by Apple to simulate Apple devices. Similarly Android devices we have emulators.
Now, if you are only concerned with the design and layout of the website then you must try LambdaTest. They provide platform for you to test your website for responsiveness and visual bugs on variety of emulators and simulators.