Please is a very flexible word -- it can be used in several different places in a sentence.
Please is correctly used in each of the following sentences:
Can I please put you on hold?
Can I put you on hold, please?
Please, can I put you on hold?
The last example is used less frequently than the other two, but it is idiomatic English.
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Here is another example:
Come in, please. = Please, come in.