Your question is a bit... odd; and can be interpreted/used in differing ways, depending on what nation and mindset you're referring to.
Since I'm a US citizen, and it's election season, and righties throw the term around without understanding it.
I will discuss it in the context of US politics.
The USA has a combination of Socialistic and Capitalistic practices. The economy is almost entirely based upon Capitalism, (and neither party is trying to change that, regardless of the completely brain-dead fear-mongering that the righties vomit up each day). However, for some situations, capitalism is a bad choice.
The most well known example is Fire Departments. In the US they used to be private companies, like insurance companies (or the mafia). If your house or business was burning down, the local FD shows up and checks to see if you're up to date on your local FD bills. If not, then they would discuss contracts while their crew stood around and watched your home go up in flames. Pay, and they'll work to put out the fire and rescue your dying children.
No Bueno.
So local governments took over the process, and tax funds were used to pay Fire Departments, and the FD would respond rapidly to EVERYBODY, since the people have already paid their 'bills'.
So now, all FDs are a socialistic aspect of our capitalistic nation. They don't really represent "Socialism".
Similarly, many activities that we all need, but people don't like to deal with, and/or its hard to profit from, and/or it creates a serious concern about impropriety. Such as light-house staff and maintenance; paying the cops; maintaining a HUGE military; maintaining every single road and flood-controlling culvert; etc...etc.... All of these things are not Capitalistic yet NEED to exist or civilization crumbles (fast). So we all pitch in and pay for them with our taxes.
Capitalism of course benefits immensely from it. Harbors and airports, roads and railroads - all built by the government, using tax dollars from the people. It's hard to sell refrigerators or car engines if you make a million in your factory and warehouse, but can't ship them out. And of course, how did you get all of those supplies shipped in in the first place? Including the materials you used to build the factory and warehouse?
Research and Development are also usually led by government investments (tax dollars). The military and NASA are always coming up with VERY EXPENSIVE news ways of doing things, trying to stay on the cutting edge of technology. And after they make the new thing, they let US companies use the technology to create factories and try to sell off their inventions for a profit.
Have you ever used/bought any of these military inventions? Ever heard of any private companies making a profit from their sale?
Radar
Microwave ovens
Blood plasma transfusions
Duct tape
Electric razors
Super glue, Canned food, Freeze drying, Frozen juice concentrate, Drones, Jet packs, Jet engines, EpiPens, Bug spray, Cheetos, and WD-40.
the internet.
How about NASA inventions - like cell-phones with cameras, CAT scanners, LED lights, athletic shoes, home insulation, water purifiers, portable computers, artificial limbs, baby formula, etc...etc....
Or how about basic research by government scientists in public universities and hospitals? Know any Capitalistic companies who profited from making vaccines? They didn't invent that.
In the US, the right-wing children have thrown around "socialism" and "socialist" as an insult for many years now. But our capitalism NEEDS these socialistic features to even remotely come close to competitive standards.