Communication is classified on more than one basis. Its types are as follows:
I. On the basis of relationship between the parties
a. Formal Communication    
It is an officially prescribed communication method. The communication should flow through the path, prescribed systematically. In this type of communication, the employees should communication matters only to the person mentioned therein. They should not discuss among themselves. Due to this, the information flows smoothly, accurately and timely.
b. Informal Communication
It is not an officially prescribed communication method. It takes place because of informal relations between members. This type of communication is easier and faster. But sometimes, it also spreads baseless information.

II. On the basis of flow of communication
a. Downward communication
Int this case, communication is from the higher to lower level of management i.e. policies, procedures, programmes and orders are given by the superiors to the subordinates.
b. Upward communication
In this, communication is from the lower to the higher level of management. The reports giving the details of performance, suggestions for improving working plans or policies, ideas for introducing innovations, complaints and grievances are send by the workers to the superiors.
c. Horizontal communication
It is also known s sideward communication or crosswise communication. Gene really, it takes palace in a decentralized organisation. This type of communication takes place between two managers working at same level or having same rank or status. They exchange information about many things related to work. The purpose of this communication is to secure co-ordination in operation.
d. Grapevine
In every organisation an informal channel of communication called the grapevine is in operation.
It is quite natural for a group of people working together to be interested in one another and talk about appointments, promotions, retrenchments or  even domestic affairs. Some people derive great pleasure from gathering such ‘secret’ information and transmitting to others.
e. Consensus
Consensus means agreement of opinion, testimony etc., A consensus is possible only when a group, an organisation, a committee, a meeting or a conference is friendly and homogeneous.
In communication skills, to arrive at a consensus is very important. Hence, a manager must develop this art of arriving at a consensus when dealing with a group of men. The skill lies in making others feel that the manager is democratic.
III. On the basis of methods used for communication
a. Oral Communication:         Oral communication is a more effective method for conveying ideas, feelings, suggestions and information etc., the verbal communication is made in the following ways:

•  Face-to-face conversation
•  Interviews
•  Joint consultations
•  Public communication and broadcasts

Merits

• It saves time and money
• It gives communication a personal touch
• It is suitable for removing false opinions
• It is suitable for communicating confidential matters.
• It is flexible.

Demerits

• It is difficult if the sender and receiver are at far away places.
• It is not suitable for giving lengthy explanations about policy decisions.
• If the matter of communication is to be kept on record, oral communication will not be suitable.
• There is a change for misunderstanding and misinterpretation.

b. Written communication: Written communication is the important mode of communication for conveying ideas, information etc., it is useful when the information or messages require evidence.  This communication takes place through orders, instructions and reports.
Merits

• It is a better mode of communication for persons at far off places.
• It is suitable for giving a lot of information.
• If the subject matter is to be preserved for future, it is a suitable method.
• It can be used again and again for any reference.
• There is no chance for misinterpretation since everything is in writing.

Demerits

• It is too lengthy, since it discusses each and every point.
• There is no possibility for making changes.
• It cannot be kept as a secret.
• It does not have personal touch.
• It is not flexible.