The imperative mood is used to demand or require that an action be performed. It is usually found only in the present tense, second person. To form the imperative mood, use the base form of the verb.
Heat the water to 65°C before adding the sample.
The imperative mood is very powerful. It is often appropriate to use the imperative mood when giving instructions. However, in other types of documents, such as letters, procedures, or recommendations, the bare imperative may be too strong. To tone down the effect of the imperative, you can use "politeness" words, such as please, or rephrase in the indicative with an auxiliary verb such as would.
Send the relevant documents to us as soon as possible.[This imperative might be received by some readers as being too direct, and thus, impolite.]
Would you please send the relevant documents to us as soon as
possible? [This request is more polite than the previous one.]