"mostly provide" is a correct and usable phrase in written English.
You can use it when you want to emphasize that something is mostly, but not entirely, the case. For example, "Our instructors mostly provide virtual classes, but there are still some in-Person options available for those who prefer them."
For the men, these sanctuaries mostly provide, for a few hours at least, the illusion of back home.
But these assorted artworks and artifacts mostly provide a beautifying frame for a radiantly simple wrap-around apron-dress by the artist Andrea Zittel, displayed on a mannequin.
Biennales, this one included, mostly provide cheerful, multinational chaos -- chaos ensured by the fact that there is a main show, organized by a guest curator, and separate pavilions, organized by individual countries.
Of course, historical tidbits like the 1893 Chicago World's Fair, homesteader hardship and the relative debating talents of Lincoln and Douglas mostly provide a jump-off for self-reflection.
The mainline fleet, by the way, is defined as an airline's full-size jets, in contrast with the smaller regional jets that mostly provide feeder service, usually between midsize and smaller airports and major hubs.
But to ensure slick connections at peak hours for high-fare business travellers, aircraft have to hang around at hubs.Low-cost point-to-point carriers mostly provide flights between two places, without the swift connections available at a hub relying on low fares to attract enough business.
In primary health care the services purchased form private sector are mostly provided by for-profit providers.
For now, the site mostly provides information about traveling and shopping abroad.
Melbourne Victory's imports have mostly provided more value than their rivals.
Christian is underused as background noise: mostly providing coyote calls and drawn-out double-bass.
Health care spending, which mostly provides comfort to those beyond working years, is expanding.
