About Password Manager
A password manager is a software application that is used to store and manage the passwords that a user has for various online accounts and security features. Password managers store the passwords in an encrypted format and provide secure access to all the password information with the help of a master password.
There are many types of password managers, differing in the way they encrypt the information, type of storage and the additional features provided.
Password managers enable the use of strong and unique passwords for each online account and provide an efficient way to manage all the passwords. The login information is encrypted and stored in either the local memory of the user’s system or in cloud storage. Portable password manager applications installed in mobile devices can also be used as a way to manage and remember passwords anywhere and use them on shared systems.
Password managers usually incorporate some additional features like automatic form filling and password generation. The automatic form filling feature fills in the login information for a particular URL whenever it loads, and thus reduces manual errors and protects systems from hacker attacks such as keylogging. As password managers can identify the right URL for a particular login ID and password pair automatically, they are capable of protecting credentials from phishing sites.

KeePass - Password Manager
KeePass is a free open source password manager, which helps you to manage your passwords in a secure way. You can put all your passwords in one database, which is locked with one master key or a key file. So you only have to remember one single master password or select the key file to unlock the whole database. The databases are encrypted using the best and most secure encryption algorithms currently known (AES and Twofish).
We recommend keepass for advanced secure encryption algorithm, simple and better user experience.

Step 1: Open Keepass and enter Master password used when generating the password Database.

Step 2: Select the Password that need to be changed, Right click to open short-cut menu, select Duplicate enty. Creating a duplicate entry allows us to retain the old password.(Skip this step if keepass was not used for generating old password)

Default the values in the following screen and click on OK.

Step 3: Select the password entry which was used for generating Duplicate entry, select Edit/View entry and generate new password. (Skip this step if keepass was not used for generating old password)

Click on Generate Password icon and click on Derive from previous Password menu.

Step 4: Select the above created copy of old password entry, right click and copy password. (Skip this step if keepass was not used for generating old password.)

Step 5: Paste password into old password field, in this example we are using change password for gmail.(Skip this step if keepass was not used for generating old password)

Step 6: Select newly generated password entry and copy password

Step 7: Paste password into new password field in required application / website, in this example we are using change password for gmail.

Step 8: Post successful password change, select duplicated password entry and Delete entry.