Different type of income considered for income tax are-
a) Income from salary,
b) Income from property, for example income from house rent,
c) Profits earned in business and profession,
d) Capital earning and
e) Earnings from other sources.
Your next query is regarding the residential status of tax payers. Tax payers are classified into three categories i.e.
1) Residential and ordinary residential,
2) Residential but non ordinary residential and
3) Non residential.
Residential status is allotted to a person other than individual. Type of person may be Hindu Undivided Family ( HUF ), Firm, Association of persons, Indian company, Foreign company and any other person other than individual.
HUF residential status categorization-
a) If taxpayers business affairs are wholly in India then it is residential,
b) If taxpayers business affairs are wholly outside India then it is non-residential and
c) If taxpayers business affairs are partly in India and partly outside India then also it comes under residential status.
For all type of person categorization is same as in case of Hindu Undivided Family except Indian company and foreign company. for Indian company status is only residential whether taxpayers business affairs are in India or outside India wholly or partly.
Foreign company business affairs are in India the it is considered in residential status. otherwise it is non residential. Income earned India is always taxable in India not withstanding with residential category and income earned outside India is not taxable for non residential Indian. If a person is resident but not ordinary resident then his income is taxable only if his business affairs are in India wholly or partly.
Your last query whether income from agriculture is exempted from income tax. Income from agriculture is exempted from income tax but in few cases income from agriculture is considered partly a business affairs. For example growing and manufacturing tea in India is partly agricultural income and partly business. Same is the case with many more products like coffee and rubber etc.