Training or internship is mandatory in B.Tech as per AICTE. Generally, one viva is arranged either in the 7th semester or the 8th semester. You have to appear the viva with a report. In the report, you write about the processes or machines of the visited industry or factory or research organization. Due to COVID, we are stuck inside houses. You have missed the training or it is delayed. The training period in various organizations has almost passed as the summer is coming to an end. The problem will come when you have to submit the report along with the certificate in the viva. As you cannot go for training physically, you can do some online courses related to mechanical engineering. You can do various courses on designing (Autocad,) and programming (C, Python, Java, CNC, Arduino,) immediately online. There are some reputed sites where you can do courses. These are listed below.
(1) Coursera
(2) EDX
(3) Swayam
(4) Udemy
You will get a certificate upon completion of the course with the payment of nominal fees. These courses are offered by reputed universities like Havard, MIT, Carnegie, Colombia University, etc. Swayam is an Indian platform. The government of India is pushing online education in massive ways. You can avail of the facility of the courses there also. These certificates can be easily translated to internships looking at the pandemic condition. For more articles related to B.Tech, you can have the eBook available on amazon.