The word "anda" is used very often in colloquial Spanish to express different things. It can indicate surprise, disbelief, rejection, admiration, emphasis, irony...
These are the main contexts where it is used:
Anda: to encourage/ask someone to do something.
Anda: to show surprise or admiration
Anda que, anda que no: to express something with irony/sarcasm
Note that depending on what they convey, these expressions using anda, anda que, anda que no, can have very different translations as there is no direct equivalent in English.
Anda is an invariable word in these cases, coinciding with the imperative form of the verb andar, but here is is used as an idiomatic expression and is completely disconnected from the meaning "to walk".
There are short expressions using the word anda that are used on their own as exclamations, meaning different things depending on the context. For example:
Want to make sure your Spanish sounds confident? We’ll map your knowledge and give you free lessons to focus on your gaps and mistakes. Start your Braimap today »