How does one learn to market themselves this way? I come from a culture that values privacy & humility and it's really hard to express myself in public like thi

How does one learn to market themselves this way? I come from a culture that values privacy & humility and it's really hard to express myself in public like this. I have no trouble doing it IRL, but doing it online just seems... wrong to me. I understand that if I want to sell products, people need to find out about it someway and good marketing is what drives people to your product, but it just seems like such a foreign language to me.