If possible you should record the interview as a WAV file, and note that recording as mp3 or mp4.
Converting to WAV will not produce an audio file with equivalent quality to recording directly as a WAV file.
When using video software the quality of the audio will not be of professional quality, and will not be at the recommended oral history specification of WAV files at 48 kHz, 24 bit.
In-built microphones in computers and laptops will likely be of poor quality.
If both you and your interviewee can use external microphones (or a headset with a built-in microphone) your interview will be of significantly better audio quality
The volume levels of the interviewer and the interviewee are likely to have greater variation in a remote interview than in a face-to-face interview. Consider how you can minimize this, for example by recording to a stereo track where the levels can be adjusted individually after the recording has finished (which is not possible in a mono track).
To have a good quality Zoom call, you will probably need a minimum download/upload speed of 75/8 Mbps (megabytes per second). Note that fiber optic connections can have much lower bandwidth needs, around 25 Mbps.
Audio Recording Tips
The one piece of equipment that makes the difference between an audible and an inaudible recording is an external microphone.
Unless the interview circumstances require the interview to be conducted while walking or moving about, an expensive wireless microphone is not necessary; one that simply plugs into the recorder will work well.
The recorder does not need to be expensive, but it must have two essential features: a microphone outlet and the capacity to deactivate the "voice-activated" function.
Before conducting the first interview, practice recording with the equipment.
Conduct the interview in as quiet a place as possible. Sounds that may be unnoticeable during the interview will inevitably be magnified on the recording.
Do a brief test recording with the interviewee at the interview location and play it back immediately.