Where can I report system defects?

Hi!

Where can I report system defects?

I want me and others to get the most out of their iPhone (:

I found two drawbacks to the system. Situation description:

I get an SMS. Sometimes when I switch from another application to read a message, the keyboard does not appear.

Another situation: when the phone is connected to the portable loudspeaker (JBL Charge 5), the volume of incoming messages and calls decreases. Even when I give a louder sound, after disconnecting from the speaker and reconnecting it again, the sounds are quieter again.

whatsapp - sometimes has a problem with displaying subtitles before entering chat with a person