Please recommend it as a second mobile phone

I am currently using the LG G7. I am thinking of the iPhone 6s as a sub-cell phone. Is it okay?

iPhone 6s is pretty okay. It'll get you from a to b. If you're buying from someone, I'd hold off since it's likely too old. The battery will likely be bad. As for handling common apps like facebook and youtube, it'll do the trick. I wouldn't expect to be able to play any games though since its OS is outdated. I'd recommend google's pixel 3a. It's cheap and powerful. Also google pixel 3 is 300 bucks off until the end of september.

Iphone 6s is okay, but I would recommend iphone SE, its small, compact and super fast when using it properly

Iphone 6s is okay, but I would recommend iphone SE,agree with that

Iphone 6 is ok, but if your open for suggestions try Xiaomi Mi9T Pro

I suggest Xiaomi. It's cheap and the phone quality is the best.

I recently purchased an iPhone 6s and I have to say it's probably the best iPhone ever made for the sole reason that it's the newest version that actually comes with a headphone jack. Before I bought the iPhone, I used an LG K8 which is a low-mid range Android. It was pretty slow but I guess it got the job done.

smartphone with a longest battry usage 6000 mah i recomend

I mean if it's just a secondary phone could you use a brick phone like one of those small Nokia 3310 etc.

samsung s8
samsung s9
samsung note series
iphone series maybe ???