Yes and No.

Most receivers output an analogue signal, I believe it just varies in amplitude between 0V and 5V. That is great for just plugging straight into normal analogue servos.

But, you can potentially reflash the firmware on the receivers to output PWM signals.

Why would PWM be useful in this case? Much greater resolution than the analogue signal, less error in the system - if the servo can resolve down to 1us with 1000us pulses, you get 0.3 degrees per 1us, and can then control the servo to that accuracy (in theory!) - the analogue servo would need a resolution of 5mV to do the same thing.

My only experience with this is with FrSky receivers, and in that case the PWM output wasn't just on a per-channel basis, it would instead send all 8 channels in PWM through the first channel output - e.g. if Channel 1 was 100%, channel 2 was 0%, channel 3 was 75%, and the others were all 0% it would send a long frame, where the first 1000us would be on, the second 1000us would be off, then 750us on, then off for (5+0.25) 5250us. That setup is great if you want to send 8 channels worth of data to an Arduino or something, but you'd get some crazy servo behavior if you plugged straight into it.

TLDR; stick with analogue servos all around to make your life simple. Digital servos are probably better, but you're going to need to invest more time into ensuring the equipment is compatible first.