When in college, I got selected via campus recruitment and the company sent me an offer letter by email, to which I replied, because I knew this was a trusted source. On the joining day, they gave my appointment letter which they and I signed.
Now, after 8 years in this company, I've been interviewed and selected by a startup. They have sent me an offer letter (pdf form) by email. The people are very mature, polite and they even gave me proof of their company registration when I asked for it. They are even willing to sign the offer letter for me, and I have the option of either taking half a day leave tomorrow to collect the signed offer letter or I can just reply by email, that I accept the job offer. They have verbally assured me that even if the formality of signing the offer letter is not done, they will honour the fact that I have been offered the job.
So is it really necessary/safer to get signatures on the offer letter or does an email (it was sent from their domain id) from them and a reply from me form a proper legal agreement that the job was offered and accepted, and that I can now formally resign from my current job?