"has made suggestions" is correct and usable in written English.
You can use it when you want to express that someone has offered their ideas or opinions about something. For example, "The team leader has made suggestions for reorganizing our office space."
The group has made suggestions on how Orvana could make its plans more environmentally friendly.
The White House has made suggestions, and many governors have offered theirs.
He has made suggestions to Cogmed about making the marketing more accurate, he told me, but, "I am not comfortable with everything that is said".
George C. Loehr, a former executive director of the Northeast Power Coordinating Council, is a management consultant and member of the group Power Engineers Supporting Truth, which has made suggestions on preventing future blackouts.
"Practically everyone who has written about the Tapestry has made suggestions about Aelfgyva, ranging from the seductively tempting to, frankly, the absurd," as a site dedicated to the tapestry puts it.
The expert commission conducting the monitoring process called 'Energy of the Future' has made suggestions for indicators that are far more suitable [[8]].
Other researchers have made suggestions that reinterpret ancient hunter-gatherer societies.
"I sat down and drew that on the table with the people who had made suggestions".
I'm only an adviser, and I've made suggestions until I'm blue in the face!
I've made suggestions for which type of cabbage to use in which recipes, but you should feel free to substitute.
Greig wanted it "made clear" that she was not responsible for the decision to broadcast the call and that before the broadcast she had made suggestions for changes.
