Pitch Is One Piece of the Puzzle
Keep doing your previous exercises every day, but when you are ready for something more, you can start working on pitch - how high or low your voice is. Pitch is just one of many elements, and not even the most important, but it is probably the most well-known difference between the average male and female voice.
Aim for stable conversational pitch in the female range, not exaggerated highs that force strain. Resonance, articulation, and intonation are equally important, so treat pitch as one dial in a larger system.
Registers: Chest, Falsetto, and Mix
In addition to pitch, your voice locks into different registers at different points in your range, each with a different sound quality. Watch this video to hear the differences between chest voice, falsetto, and mix voice (which is technically part of your modal register, same as chest).
Follow along with the warmups in this video, then try switching between registers a few times, both singing and speaking.
You might find that you start in modal register in the male range but flip into falsetto to reach the female range. Or you might have to strain and shout to get that high. If either happens, go back down to the pitch where you can still speak comfortably in modal register and do not worry about going higher for now.
Using a Pitch Monitor
Download Vocal Pitch Monitor on Android or iOS. In the settings, change the Scale to F Major and check the box to display frequency in Hz.
With the app running, talk in your starting voice and see where your pitch falls naturally. A typical male speaking voice stays between F2 and F3 (marked by horizontal lines since we set the scale to F Major). Now try talking higher until your voice is in the female range, around F3 and above. Do not go higher than F4 though, or you will sound like a cartoon character.
Observe trends across days instead of chasing perfect values every sentence. If your voice flips or tightens, lower the target slightly and rebuild consistency in modal production.
Daily Speaking Practice
Set aside some time every day - say half an hour - to warm up with the register video above and then practice speaking in the female range (between F3 and F4), or as close as you can get without straining or going into falsetto. You can say random things, recite lines from memory, or read a book or comments out loud while keeping an eye on Vocal Pitch Monitor.
It might sound terrible, and that is okay. The important thing is to get used to speaking in that range. Drink water throughout and take a break if you feel your voice getting strained or hoarse.