You don't need a mic to record. While it is true how to connect the amp to your PC depends on what outputs your amp provides, it is most likely possible without a mic. Most current amps have at least a headset jack. Some with have additional outputs.

For me, I run a male mini plug stereo cable (like this one) from the amp headset jack to the input on my PC sound card. That being said, you will still need some software to record it.

At might be a little harder with your phone. Since you didn't specify, I will just offer this generic answer: you will need some type of adapter like this 1/8 to usb.

While it is true how to connect the amp to your PC depends on what outputs your amp provides, it is most likely possible without a mic. Most current amps have at least a headset jack. Some with have additional outputs.

For me, I run a male mini plug stereo cable (like this one) from the amp headset jack to the input on my PC sound card. That being said, you will still need some software to record it.

It might be a little harder to record with your phone, but still achievable. Since you didn't specify, I will just offer this generic answer: you will need some type of adapter like this 1/8 to usb.

If you can update your post with your amp, and pc model and even your phone model, I can probably give you more concrete suggestions.