As an addendum: Japanese isn't as all-in on pitch having semantics as Chinese, but pitch is very important. Words have "pitch accent" rather than "stress" the way English has, and overall pitch is strongly politeness-coded.
Speaking higher is politer, and noticeably dropping your pitch is threatening. You probably would pitch-up when speaking to your boss, and people working in shops or restaurants nearly sing welcome/thank you for coming type things.
Don't be smartass. My question was how to change pitch? Most people can't change their pitch unless they have been trained. I can't speak with the pitch of child or woman. Neither are most people.
Comparing our culture to others, women in the U.S. are raised to do much the same. Ask anyone woman constantly misgendered for not having a high-pitched woman’s speaking tone (e.g. pacific islanders) and they’ll confirm. Best not throw stones from glass houses.
Sure, I've been here for almost 20 years. It doesn't change a fact it sounds stupid. I asked two colleagues from Japan and they both agreed this probably wasn't done by a japanese person.