可以在UILabel的Category中提供如下几个方法:

.h文件

@interface UILabel (ChangeLineSpaceAndWordSpace)
/**
 *  改变行间距
 */
+ (void)changeLineSpaceForLabel:(UILabel *)label WithSpace:(float)space;

/**
 *  改变字间距
 */
+ (void)changeWordSpaceForLabel:(UILabel *)label WithSpace:(float)space;

/**
 *  改变行间距和字间距
 */
+ (void)changeSpaceForLabel:(UILabel *)label withLineSpace:(float)lineSpace WordSpace:(float)wordSpace;

@end

.m文件

@implementation UILabel (ChangeLineSpaceAndWordSpace)

+ (void)changeLineSpaceForLabel:(UILabel *)label WithSpace:(float)space {
    
    NSString *labelText = label.text;
    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:labelText];
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    [paragraphStyle setLineSpacing:space];
    [attributedString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [labelText length])];
    label.attributedText = attributedString;
    [label sizeToFit];
    
}

+ (void)changeWordSpaceForLabel:(UILabel *)label WithSpace:(float)space {
    
    NSString *labelText = label.text;
    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:labelText attributes:@{NSKernAttributeName:@(space)}];
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    [attributedString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [labelText length])];
    label.attributedText = attributedString;
    [label sizeToFit];
    
}

+ (void)changeSpaceForLabel:(UILabel *)label withLineSpace:(float)lineSpace WordSpace:(float)wordSpace {
    
    NSString *labelText = label.text;
    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:labelText attributes:@{NSKernAttributeName:@(wordSpace)}];
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    [paragraphStyle setLineSpacing:lineSpace];
    [attributedString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [labelText length])];
    label.attributedText = attributedString;
    [label sizeToFit];
    
}
@end

附: 在Xcode8中创建Category文件的方法:

在工程目录中右键选择New File...或者使用键盘command+N, 然后在弹出窗口中选择Objective-C File

新建文件

然后

起名字, 选择Category, 并选择要扩展的类

最后

设置好后点击Next完成