Learn Italian: Potete fare un investimento sicuro. - You can make a safe investment.

It comes from the verb investire (to invest). To form a noun that describes the action or result of a verb, Italian often adds the suffix -mento to the verb's stem. Notice that nouns ending in -mento are almost always masculine, which is why it uses the article un.

Why do we use fare here to translate "to make"?

The standard Italian expression for "to make an investment" is fare un investimento. Italian relies heavily on the versatile verb fare (to do/make) for completing actions and processes. You could also express this idea by just using the verb on its own, like Potete investire in modo sicuro (You can invest safely).

Does placing sicuro after the noun change its meaning?

Yes, slightly. Placing a descriptive adjective after the noun gives it a literal, objective meaning. Un investimento sicuro categorizes the investment as financially safe or low-risk. Placing it before the noun (un sicuro investimento) would sound more subjective or emotional, emphasizing the speaker's certainty, like "a sure-fire investment."

Why is it Potete fare and not Potete fate?

Potere (can/to be able to) is a modal verb. When it is conjugated to match the subject (here as potete for "you all"), the main action verb that directly follows it must always stay in its infinitive (dictionary) form, which is fare.