I have to agree that pitch is only part and can be overcome with other clues. Just as if you are 1m90 tall, you still can "pass" if more of the other things are right. Of course if you are 1m90 tall, have a masculine voice, wide shoulders, short hair and masculine facial features, it will be too hard. "Passing" is always about balancing out masculine features with female features and so a voice can sound female even if it is not sounding feminine but rather has a lower female range pitch. Of course below maybe a low C (130 Hz), that will not work, so it should be at least somewhere around the E or 150 Hz to make this work, but that is a pitch that almost all people with a masculinized voice can reach.
From there two main issues arise: resonance and prosody. Resonance means that the voice should resonate fore in the upper area - head, throat, mouth (but not too much nose or you sound nasal or "stereotypical gay") rather than in the lower throat or chest. There are some ways to train this and it can become second nature. I learned this with "Melanie Anne Phillips Voice tapes" back in the 1990ies, but they still exist as an updated version in MP3

- the other good program to train it is "Finding your female voice", which uses a bit of a different approach, but they aim a bit high at the pitch, there is no need to target 200 Hz and sadly the FYFV instructions are a rather boring and long exercise, so I would try the other one first, which would be a shortcut, if it works for you.
With a more forward resonance and a pitch in the "upper male" or gender neutral range (150-170 Hz) you should already be perceived as female most of the time when your appearance matches this. It may still be hard on the phone though.
The second big part is prosody, meaning the way you speak. Intonations, voice melody, pitch range. For me, getting this right was mostly about basically reall believing that I am a woman truely (not thinking of myself as "trans") and then let go of old habits, allowing my voice to express itself more. But it may help to train this a bit by either trying to emulate speakers that sound cleraly female on TV or Radio - Audiobooks are great too, because female speakers speaking female characters there often use almost overemphasized female prosody to make the character more alive. Talk after them - see if you can match their voice melody and intinations without matching their pitch (!). You cannot get a female prosody if you force your voice in a pitch range that is already hard to reach. Its a bit like lifting a heavy weight and then dance - its much easier to just carry a little weight and then dance, because you will have to do both - lifting weight (raising pitch) a little, and dance (using a wide pitch range for voice melody). As a sidenote this is why I got voice surgery because basically it "lifts part of the weight for you" and so you are more free to dance

Good luck

Oh and for fun, contra to the videos above of men sith nearly female voices, here is a woman that has a very low voice - but in my opinion she still would mostly be identified as female by most people, but her voice seriously is as low as my voice was originally...