What is law for sole proprietor to pay income tax ?

You have first said its a company. Then you have mentioned that you have obtained service tax registration as a Sole Properietor. You need to clarify the status of your enterprise. If you are not aware of the status, then you could comment below the 4th letter of the PAN alloted to your enterprise 'GoBulky' [I do not want to ask for your PAN on a public forum].

The answers to your question are as follows:

1. From your website, it seems you are providing Web-Designing services and like services. So you have to charge service tax on your invoice for any service provided to your foreign clients.

However, with reference to Service Tax Rules, and Rule 3 of the ST(Place of Provision of Service)Rules,2012, you may be exempted from service tax liability under Rule 4 of Service Tax Rules 1994, if ALL the following conditions are satisfied:

a) Your Regd office is located in India (except J&K)

b) Your clients are located outside India,

c) the place of provision of the service is outside India - Yes in your case, IF you dont provide Database retrieval services, etc.,

d) the foreign clients are paying you in convertible foreign exchange within time allowed by RBI (usu 1 year), and

e) Your clients are not merely branches of your own enterprise located outside India.

f) You have not claimed CENVAT Credit on your inputs & input services.

2. Yes. You should keep a record of all invoices issued by you to these foreign clients. Your income shall be subject to Income Tax. But taxability under Income Tax Act, depends on whether you are located in a SEZ or the DTAA, India has with the country of your clients.

3. No. There are no limits to what you can receive. However, there may be time limits specified by RBI, within which you have to realise the invoice proceeds.

There may be other crucial info about your business which you may have missed out above, based on which my advice above could vary. Hence I strictly suggest you approach an Expert to straighten things out. The above details are only a general idea of what you are dealing with.