Is the second division mentioned in my mark sheets acceptable for the application in Germany for a Master's/Bachelor's?

It depends. In Germany, most Master's programs require a Bachelor's degree with at least a "good" grade (typically 2.5 or better on a 5-point scale). A "second division" mark - like your 6.6/10 - may or may not meet this, as some universities accept grades up to "satisfactory" (3.5) but others are stricter.

Admission criteria vary by university and program. Some may consider your profile, especially if you meet other requirements or have strong work experience.