Waqf signs (ج، قلى، صلى، لا، م) in the Quran guide reciters on where to pause or stop during recitation, a key aspect of Tajweed called "الوقف والابتداء" in Arabic. However, their placement varies across Mushafs due to differing scholarly interpretations and regional traditions.

Fun fact: early Quranic manuscripts didn't include dots, diacritical marks (Tashkeel), or waqf signs, as native Arabs didn't need them. However, as Islam spread and non-Arab converts began learning Arabic, there was a need for enhanced clarity in distinguishing between similar-looking letters. Therefore, dots, diacritical marks and waqf signs were gradually incorporated into Quranic manuscripts to facilitate accurate recitation and comprehension.

Waqf signs were added to the Quran later on.

Images source: easyquran