Formative assessment
refers to a wide variety of methods that teachers use to conduct in-process evaluations of student comprehension, learning needs, and academic progress during a lesson, unit, or course. Formative assessments help teachers identify concepts that students are struggling to understand, skills they are having difficulty acquiring, or learning standards they have not yet achieved so that adjustments can be made to lessons, instructional techniques, and academic support.
The general goal of formative assessment is to collect detailed information that can be used to improve instruction and student learning while it’s happening. What makes an assessment “formative” is not the design of a test, technique, or self-evaluation, per se, but the way it is used—i.e., to inform in-process teaching and learning modifications.

Formative assessments are commonly contrasted with summative assessments, which are used to evaluate student learning progress and achievement at the conclusion of a specific instructional period—usually at the end of a project, unit, course, semester, program, or school year. In other words, formative assessments are for learning, while summative assessments are of learning. Or as assessment expert Paul Black put it, “When the cook tastes the soup, that’s formative assessment. When the customer tastes the soup, that’s summative assessment.” It should be noted, however, that the distinction between formative and summative is often fuzzy in practice, and educators may hold divergent interpretations of and opinions on the subject.
to evaluate students’ work or their understanding of course concepts
to communicate to the student how well their work or understanding compares to stated criteria or to other students’ work
The process of arriving at a grade for a student (either for a test or assignment, or for an entire course) is known as summative assessment. Summative assessments (e.g., exams or term papers) are formal, usually graded, and focused on letting students show a range of skills and knowledge. They require a considerable investment of time, both from students and from instructors, and are consequently often completed outside of class.
Summative and Formative Assessment
Although many instructors think of assessing student learning as synonymous with the process of arriving at a grade for student work, assessment can be used for other purposes and in other ways as well
Summative Assessment VS Formative Assessment
https://drive.google.com/file/d/1zQY8WDLlS1g6WROqxveLLUQiQj2Knm5-/view?usp=share_link

REFERENCE:
https://www.edglossary.org/formative-assessment
https://youtu.be/h8O0hQ32IIQ
https://dpi.wi.gov/sites/default/files/imce/strategic-assessment
https://citl.indiana.edu/teaching-resources/assessing-student-learning