In arabic you can reveal Masculin from feminin just from the word itself for example , in english if we say : a teacher We can't reveal if it's a feminin teacher or masculin but in arabic , if you say معلمة so it's feminin So , هذا هذه is only demonstratives , in fact adding a ة will make the word feminin

Welcome, Hope! :) Yes, it's called a "taa' marbuTa" and it shows what words are feminine. As your vocabulary grows, you will learn that there are exceptions, of course. Not every feminine word ends with a "taa' marbuTa", and there are some masculine words with one. Most of them follow the pattern of your example.

Correction: This is a (male) teacher. هَذَا مُعَلِّمٌ (mo'alim instead of mo'alam) This is a (female) teacher. هَذِهِ مُعَلِّمَةٌ (mo'alima instead of mo'alama) اللام تكون مكسورة، يعني الكسرة تحت الشدة وليس فوقها And concerning "ة" it's the same, we add it for the feminine case

When it's a feminine noun , we add ة at the end of the word. for example: معلم ، معلمة طبيب ، طبيبة أستاذ ، أستاذة محاسب ، محاسبة

for the same reason (because of masculine and feminine nouns) ex. he is an engineer هو مهندس she is an engineer هي مهندسة good luck :)