Manual Testing means whatever the condition is executed without taking any help of automated testing software and any automation testing script then it means this is manual testing.
Like some test cases are written to test software and further test cases will be executed by manually then it means it is manual process to test application.
In simple way it is that process where test cases will be executed without using any automation software and whatever the test condition will be executed without integrating any automated testing framework and done by manually then that is called manual testing.
With a simple practical example: Like a user registration form is implemented with some fields like “Name, Email and Phone” and test cases are created to execute. Suppose a positive test case is written like “Enter valid name in name field, enter valid email in email field and enter valid phone in phone field”, and when tester enter values manually and execute this test cases by hitting sign up module then it means this is manual testing because tester entered values without using any automated script, so that is why it is called manual testing.