Concept:
A sentence can perform different functions such as requesting, suggesting, ordering, apologising, or complaining.
The sentence
\[
\text{Shall we go for a movie?}
\]
is used to make a suggestion.
Step 1: Understand the sentence.
The speaker is not giving an order.
The speaker is proposing an idea:
\[
\text{going for a movie}
\]
Step 2: Identify the function.
The structure
\[
\text{Shall we... ?}
\]
is commonly used for suggestions.
Step 3: Final answer.
\[
\boxed{\text{suggesting}}
\]